FinalPermitGCPPDS2022.pdf

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ADEQ Inventory No. 10785 Permit No. AZ0026280

LTF No. 92471 Place ID No. 1494

AUTHORIZATION TO DISCHARGE UNDER THE

ARIZONA POLLUTANT DISCHARGE ELIMINATION SYSTEM

In compliance with the provisions of Arizona Revised Statutes (A.R.S.) Title 49, Chapter 2, Article 3.1; the Federal Water

Pollution Control Act, (33 U.S.C. §1251 et seq., as amended), and Arizona Administrative Code (A.A.C.) Title 18, Chapter

9, Articles 9 and 10, and amendments thereto, to protected surface waters in Arizona that are WOTUS.

U.S. Bureau of Reclamation Glen Canyon Field Division

P.O. Box 1477 Page, Arizona 86040 is authorized to discharge treated non- domestic wastewater from the Glen Canyon Dam and Power Plant located approximately 2 miles north of Page on U.S. Highway 89, in Coconino County, Arizona to the Colorado River in the Colorado River Basin at:

Outfall No. Latitude Longitude Legal

001 36˚ 56’ 24” N 111˚ 29’ 12” W Township 41N, Range 8E, Section 24 in accordance with effluent limitations, monitoring requirements and other conditions set forth herein, and in the attached “Standard AZPDES Permit Conditions.”

Annual Registration Fee [A.R.S. 49-255.01 and A.A.C. R18-14-104]

The annual registration fee for this permit is payable to ADEQ each year. For the purposes of the annual fees, this permit is a Minor permit. Send all correspondence requesting reduced fees to the Water Quality Division of ADEQ. Please reference the permit number, LTF number and why reduced fees are requested under rule.

This permit shall become effective on _________________________________________, 2022.

This permit and the authorization to discharge shall expire on ________________________________, 2027.

Signed _________________________________________________________________.

Trevor Baggiore, Director Water Quality Division Arizona Department of Environmental Quality

PERMIT NO. AZ0026280

Table of Contents

PART I. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS

A. Effluent Limitations and Monitoring Requirements

B. Trace Substance Monitoring

C. Whole Effluent Toxicity Monitoring

D. Effluent Characterization Testing

E. Surface Water Quality Standards

PART II. MONITORING AND REPORTING

A. Sample Collection and Analysis

B. Reporting of Monitoring Results

C. Twenty-four Hour Reporting of Noncompliance

PART III. WHOLE EFFLUENT TOXICITY TESTING REQUIREMENTS

A. General Conditions

B. Chronic Toxicity

C. Quality Assurance

D. Toxicity Identification Evaluation (TIE)/Toxicity Reduction Evaluation (TRE) Process

E. WET Reporting

PART IV. SPECIAL CONDITIONS

A. Operation

B. Mixing Zone Conditions

C. Reopener

Appendix A. Part A: Acronyms

Appendix A. Part B: Definitions

Appendix B. AZPDES Discharge Flow Record

Appendix C. Standard AZPDES Permit Conditions & Notifications

PART I. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS

A. Effluent Limitations and Monitoring Requirements

1. The Permittee shall limit and monitor discharges from Outfall 001 as specified in Table 1 which follows.

These requirements are based on a design capacity of 0.85 million gallons per day (MGD).

Table 1.Effluent Limitations and Monitoring Requirements

Monitoring Requirement (2)(3)

Concentration Limits

Monthly Average Weekly Average

Daily Maximum

Monitoring Frequency

Sample Type

Discharge Flow

(MGD)

Report (1) Report (1) Continuous Metered

Hardness (CaCO3) -receiving water

Report [mg/L]

Report [mg/L] 1x/quarter 24-hour Composite (4)

Oil and Grease 10 mg/L 15 mg/L 1x/quarter 24-hour Composite

TSS 30 mg/L 45 mg/L 1x/quarter 24-hour Composite

Cadmium 0.36 µg/L 0.72 µg/L 1x/quarter 24-hour Composite

Selenium 2 µg/L 3 µg/L 1x/quarter 24-hour Composite pH (5) Not less than 6.5 standard units (S.U.) nor greater than 9.0 S.U.

1x/week Discrete 1x/week Discrete

Footnotes 1 Monitoring and reporting required. No limit set at this time. The average and maximum flows shall be reported on the Discharge

Monitoring forms. See Part II.B for reporting requirements.

2 Testing must coincide with the Whole Effluent Toxicity Test (WET) samples, if any, taken during that monitoring period as per Part I.C, Table 3 of the permit. See Part IV of the permit.

3 If discharge is infrequent, see Part I.D for minimum effluent characterization monitoring requirements 4 For the purposes of this permit, a “24-hour composite” sample has been defined as a flow-proportioned mixture of not less than three discrete samples (aliquots) obtained at equal time intervals during a 24-hour period. The volume of each aliquot shall be directly proportional to the discharge flow rate at the time of sampling.

5 pH must be measured at the time of sampling and do not require use of a certified laboratory. Measurements must be obtained in accordance with the applicable method and must meet all method quality assurance/quality control requirements to be considered valid data.

B. Trace Substance Monitoring

1. The permittee shall monitor discharges from Outfall 001 as specified in Table 2. Monitoring results above the Assessment Levels (ALs) listed below do not constitute a permit violation, but may trigger evaluation of

Reasonable Potential (RP) by ADEQ. The permittee shall use an approved analytical method with a Limit of

Quantitation (LOQ) lower than the AL values as described in Part II.A.4.

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Table 2. Assessment Level Monitoring

Parameter Assessment Levels (1) (2) Monitoring Requirements (3) (4)

Monthly Average Daily Maximum Monitoring Frequency Sample Type

Mercury 0.01 µg/L 0.02 µg/L 1x/Quarter Discrete

Lead 5 µg/L 10.2 µg/L 1x/Quarter Discrete

Total Dissolved Solids (TDS)(5) Source Water

Report (mg/L) Report (mg/L) 1x/Quarter Discrete

Total Dissolved Solids (TDS)(5) Effluent

Report (mg/L) Report (mg/L) 1x/Quarter Discrete

Total Dissolved Solids

(TDS)(5)

Net increase

Report (mg/L) Report (mg/L) 1x/Quarter Discrete

Footnotes 1 Concentration values are calculated based on Arizona Water Quality Standards. Monitoring and reporting required.

2 All metals effluent Assessment Levels are for total recoverable metals.

3 Testing must coincide with the Whole Effluent Toxicity Test (WET) samples, if any, taken during that monitoring period as per Part

I.C, Table 3 of the permit. See Part IV of the permit.

4 If discharge is infrequent see Part I.D for minimum effluent characterization monitoring requirements.

5 The permittee shall monitor and report both the source water and the effluent for total dissolved solids and calculate and report the difference as the net value. The difference between the two is the “incremental increase”, i.e. the increase between the source water supply and the effluent discharge. (Per the Policy for Implementation of Colorado River Salinity Standards Through the NPDES Permit Program for Wastewater Treatment Plants, adopted 10/2002 by the Colorado River Basin Salinity Control Forum).

The incremental increase shall be less than 400 mg/L or the flow-weighted average annual net salt loading shall not exceed 1 ton/day.

C. Whole Effluent Toxicity Monitoring

1. The permittee shall monitor discharges from Outfall 001 for Whole Effluent Toxicity (WET) as specified in

Table 3 which follows. If toxicity is detected above an Action Level specified as follows, the permittee must perform follow-up testing and, as applicable, follow the TIE/TRE processes in Part IV.E of the permit.

Table 3. WET Testing

Effluent Characteristic (1)

Action Levels Monitoring Requirements

Daily Maximum (2) (3) Monthly Median (3) Monitoring Frequency (4)

Sample Type

Chronic Toxicity Pseudokirchneriella subcapitata (Green algae) (5)

1.6 TUc 1.0 TUc 1x/ 2026 24-hr Composite

Chronic Toxicity Pimephales promelas (Fathead minnow)

1.6 TUc 1.0 TUc 1x/ 2026 24-hr Composite

Chronic Toxicity Ceriodaphnia dubia (Water flea)

1.6 TUc 1.0 TUc 1x/ 2026 24-hr Composite

Footnotes 1 See Part IV for additional requirements for testing and reporting Whole Effluent Toxicity (WET).

2 Since completion of one chronic WET test takes more than 24 hours, the daily maximum is considered to be the highest allowable test result.

3 If chronic toxicity is detected above the Action Levels in this table or an acute test fails, the permittee must perform follow-up testing. See Part IV for details.

4 If discharge is infrequent see Part I.D for minimum effluent characterization monitoring requirements.

5 Formerly known as Selenastrum capricornutum or Raphidocelis subcapitata.

D. Effluent Characterization Testing

1. The permittee shall monitor to characterize the facility’s effluent for the parameters listed in Tables 4.a – b, whether discharging or not. When the facility discharges, monitoring is to be conducted at the frequency indicated in Tables 1 through 3. No limits or ALs are established, but the LOQ must be low enough to allow comparison of the results to the applicable water quality standards (WQS). If a LOQ below the WQS cannot be achieved, then the permittee shall use the method expected to achieve the lowest LOQ, as defined in

Appendix A of this permit. Samples are to be representative of any seasonal variation in the discharge.

Table 4a. Effluent Characterization Testing—General Chemistry and Microbiology

Reporting Units

Monitoring Requirements

Monitoring Frequency (1) Sample Type

Biochemical Oxygen Demand (BOD-5) mg/L 1x/2026 24-hour Composite

Chemical Oxygen Demand (COD) mg/L 1x/2026 24-hour Composite

Chlorine, Total Residual (TRC) (3)(4) µg/L 1x/year Discrete

Dissolved Oxygen (4) mg/L 1x/year Discrete

E. coli cfu/100 mL (2) 1x/year Discrete

Nitrate/Nitrite (as N) mg/L 1x/year 24-hour Composite

Nitrogen, Total Kjeldahl (TKN) mg/L 1x/year 24-hour Composite

Organic Carbon, toal (TOC) Mg/L 1x/2026 24-hour Composite

Oil and Grease mg/L 1x/year Discrete pH (4) S.U. 1x/year Discrete

Phosphorus mg/L 1x/year 24-hour Composite

Temperature (discharge) (4) °Celsius Once in Summer and Winter 2026 Discrete

Reporting Units

Monitoring Requirements

Monitoring Frequency (1) Sample Type

Temperature (receiving water) (4) °Celsius Once in Summer and Winter 2026 Discrete

Total Dissolved Solids (TDS) mg/L 1x/year 24-hour Composite

Total Suspended Solids (TSS) mg/L 1x/year 24-hour Composite

Footnotes 1 If more frequent monitoring of any of these parameters is required by another part of this permit, those sampling results may be used to satisfy Table 4.a. requirements.

2 cfu = colony forming units; “most probable number” (mpn) is considered equivalent for reporting purposes 3 Sample when chlorine or bromine compounds are used for disinfection. See Part II.A.6 for specific monitoring requirements for chlorine 4 Temperature, pH, TRC and dissolved oxygen must be measured at the time of sampling and do not require use of a certified laboratory.

See Part II.A.5 for methods of analyses for chlorine. Measurements must be obtained in accordance with the applicable method and must meet all method quality assurance/quality control requirements to be considered valid data.

Table 4b. Effluent Characterization Testing—Selected Metals, Trace Substances and WET

Parameter (1) Reporting Units

Monitoring Requirements

Monitoring Frequency (2) Sample Type

Antimony µg/L 1x/year 24-hour Composite

Arsenic µg/L 1x/year 24-hour Composite

Beryllium µg/L 1x/year 24-hour Composite

Cadmium µg/L 1x/year 24-hour Composite

Chromium (4) µg/L 1x/year 24-hour Composite

Chromium VI (4) µg/L 1x/year Discrete

Copper µg/L 1x/year 24-hour Composite

Iron µg/L 1x/year 24-hour Composite

Lead µg/L 1x/year 24-hour Composite

Mercury µg/L 1x/year Discrete

Nickel µg/L 1x/year 24-hour Composite

Selenium µg/L 1x/year 24-hour Composite

Silver µg/L 1x/year 24-hour Composite

Thallium µg/L 1x/year 24-hour Composite

Zinc µg/L 1x/year 24-hour Composite

Hardness mg/L 1x/year 24-hour Composite

Cyanide µg/L 1x/year Discrete

Whole Effluent Toxicity - chronic

(all 3 species) (3) TUc 1x/ permit term 24-hour Composite

Footnotes:

(1) All metals analyses shall be for total recoverable metals, except chromium VI, which is dissolved.

(2) If more frequent monitoring of any of these parameters is required by another part of this permit, those sampling results may be used to satisfy Table 4.b. requirements.

(3) If chronic toxicity is detected above the Action Levels specified in Table 3 or an acute test fails, the permittee must perform follow-up testing and, as applicable, follow the TIE/TRE processes in Part IV.E of the permit, whether discharging or not. See Part IV for additional information on requirements for testing and reporting Whole Effluent Toxicity (WET).

(4) If total chromium exceeds 8 µg/L, the permittee must conduct sampling for chromium VI for the remainder of the permit. Otherwise, monitoring for chromium VI is not required.

E. Surface Water Quality Standards

1. The discharge shall be free from pollutants in amounts or combinations that:

a. Settle to form bottom deposits that inhibit or prohibit the habitation, growth or propagation of aquatic life;

b. Cause objectionable odor in the area in which the surface water is located;

c. Cause off-taste or odor in drinking water;

d. Cause off-flavor in aquatic organisms;

e. Are toxic to humans, animals, plants or other organisms;

f. Cause the growth of algae or aquatic plants that inhibit or prohibit the habitation, growth or propagation of other aquatic life or that impair recreational uses;

g. Change the color of the surface water from natural background levels or color.

2. The discharge shall be free from oil, grease and other pollutants that float as debris, foam, or scum; or that cause a film or iridescent appearance on the surface of the water; or that cause a deposit on a shoreline, bank or aquatic vegetation.

3. The discharge shall not cause an increase in the ambient water temperature of more than 1.0 degrees

Celsius.

4. The discharge shall not cause the dissolved oxygen concentration in the receiving water to fall below 7 mg/L unless the percent saturation of oxygen remains equal to or greater than 90%.

5. The discharge shall not cause the receiving water to exceed 25 mg/L for suspended sediment concentration.

PART II. MONITORING AND REPORTING

A. Sample Collection and Analysis

1. Samples taken for the monitoring requirements specified in Part I shall be collected at the following locations:

a. Influent samples shall be taken from the souce water, Lake Powell,

b. Effluent samples shall be taken downstream from the last treatment process at outfall 001 as well as

500 m from the outfall.

2. The permittee is responsible for the quality and accuracy of all data required under this permit.

3. The permittee shall keep a QA Manual on site that describes the sample collection and analyses processes. If the permittee collects samples or conducts sample analyses in house, the permittee shall develop a QA

Manual that addresses these activities. If a third party collects and/or analyzes samples on behalf of the permittee, the permittee shall obtain a copy of the applicable QA procedures. The QA Manual shall be available for review by ADEQ upon request. The QA Manual shall be updated as necessary to reflect current conditions, and shall describe the following:

a. Project Management, including:

i. Purpose of sample collection and sample frequency;

ii. When and where samples will be collected;

iii. How samples will be collected;

iv. Laboratory(s) that will perform analyses;

v. Any field tests to be conducted (detail methods and specify equipment, including a description of any needed calibrations); and

vi. Pollutants or analytes being measured and for each, the permit-specific limits, Assessment Levels, or thresholds, (e.g. the associated detection limits needed.)

b. Sample collection procedures including:

i. Equipment to be used;

ii. Type and number of samples to be collected including QA/QC samples (i.e., background samples, duplicates, and equipment or field blanks);

iii. Types, sizes and number of sample bottles needed;

iv. Preservatives and holding times for the samples (see methods under 40 CFR 136 or 9 A.A.C. 14, Article

6 or any condition within this permit that specifies a Chain of Custody procedures.

c. Specify approved analytical method(s) to be used and include;

i. Limits of Detection (LOD) and Limits of Quantitation (LOQs);

ii. Required quality control (QC) results to be reported (e.g., matrix spike recoveries, duplicate relative percent differences, blank contamination, laboratory control sample recoveries, surrogate spike recoveries, etc.) and acceptance criteria; and

iii. Corrective actions to be taken by the permittee or the laboratory as a result of problems identified during QC checks.

d. How the permittee will perform data review; complete DMRs and records used to report results to

ADEQ; resolve data quality issues; and identify limitations on the use of the data.

4. Sample collection, preservation and handling shall be performed as described in 40 CFR 136 including the referenced Edition of Standard Methods for the Examination of Water and Wastewater, or by procedures referenced in A.R.S. Title 9, Chapter 14 of the Arizona Department of Health Services (ADHS) Laboratory

Licensure rules. The permittee shall outline the proper procedures in the QA Manual, and samples taken for this permit must conform to these procedures whether collection and handling is performed directly by the permittee or contracted to a third-party.

5. Analytical requirements

a. The permittee shall use a laboratory licensed by the ADHS Office of Laboratory Licensure and Certification that has demonstrated proficiency within the last 12 months under A.A.C. R9-14-609, for each parameter to be sampled under this permit. However, this requirement does not apply to parameters which require analysis at the time of sample accordance with A.C.C. 36-495.02(A)(3). (These parameters may include flow, dissolved oxygen, pH, temperature, and total residual chlorine.)

b. The permittee must utilize analytical methods specified in this permit. If no test procedure is specified, the permittee shall analyze the pollutant using:

i. A test procedure listed in 40 CFR 136 which is also approved under A.A.C. R9-14-610;

ii. An alternative test procedure approved by EPA as provided in 40 CFR 136 and which is also approved under A.A.C. R9-14-610;

iii. A test procedure listed in 40 CFR 136, with modifications allowed by EPA or approved as a method alteration by ADHS under A.A.C. R9-14-610C; or

iv. If no test procedure for a pollutant is available under (4)(b)(i) through (4)(b)(iii) above, any Method approved under A.A.C. R9-14-610(B) for wastewater may be used, except the use of field kits is not allowed unless otherwise specified in this permit. If there is no approved wastewater method for a parameter, any other method identified in 9 A.A.C. 14, Article 6 that will achieve appropriate detection and reporting limits may be used for analyses.

c. For results to be considered valid, all analytical work, including those tests conducted by the permittee at the time of sampling (see Part II.A.4.a), shall meet quality control standards specified in the approved methods.

d. The permittee shall use analytical methods with a Limit of Quantitation (LOQ) that is lower than the effluent limitations, Assessments Levels, Action Levels, or other water quality criteria, if any, specified in this permit. If all methods have LOQs higher than the applicable water quality criteria, the Permittee shall use the approved analytical method with the lowest LOQ.

e. The permittee shall use a standard calibration curve when applicable to the method, where the lowest standard point is equal to or less than the LOQ.

6. Mercury Monitoring - The permittee shall use an ADHS-certified low-level mercury analytical method such as EPA method 245.7 or 1631E to achieve a reporting limit at or below the discharge limitations or assessment levels for mercury as specified in this permit. The permittee shall also use a “clean hands/dirty hands” sampling technique such as EPA Method 1669 if necessary to achieve these reporting limits.

7. Metals Analyses - In accordance with 40 CFR 122.45(c), all effluent metals concentrations, with the exception of chromium VI, shall be measured as “total recoverable metals”. Discharge Limits and

Assessment Levels in this permit, if any, are for total metals, except for chromium VI for which the levels listed are dissolved.

B. Reporting of Monitoring Results

1. The permittee shall report monitoring results on Discharge Monitoring Report (DMR) to the ADEQ electronic submission portal MyDEQ. The permittee shall submit results of all monitoring required by this permit in a format that will allow direct comparison with the limitations and requirements of this permit. If no discharge occurs during a reporting period, the permittee shall specify “No discharge” on the DMR. The results of all discharge analyses conducted during the monitoring period shall be included in determinations of the monthly average and daily maximums reported on the DMRs if the analyses were by methods specified in Part II.A above, as applicable.

2. DMRs and attachments are to be submitted by the 28th day of the month following the end of a monitoring period. For example, if the monitoring period ends January 31st, the permittee shall submit the DMR by

February 28th. The permittee shall electronically submit all compliance monitoring data and reports using the myDEQ electronic portal provided by ADEQ. The reports required to be electronically submitted include, but are not limited to, the following:

a. Discharge Monitoring Reports

b. Whole Effluent Toxicity (WET) reports

c. Original copies of laboratory results

d. AZPDES discharge flow records

e. Bench sheets or similar documentation for field testing parameters

3. If requested to participate, the permittee shall submit the results of the annual NPDES DMR/QA Study to ADEQ and ADHS for all laboratories used in monitoring compliance with this permit by December 31st of each year. The permittee shall also conduct any proficiency testing required by the NPDES DMR-QA Study for those parameters listed in the study that the permittee analyzes in house or tests in the field at the time of sampling (these parameters may include pH and total residual chlorine). All results of the NPDES DMR-QA Study shall be submitted to the email and addresses listed below, or submit by any other alternative mode as specified by ADEQ:

4. For the purposes of reporting, the permittee shall use the Limit of Quantitation.

5. For parameters with Daily Maximum Limits or Daily Maximum Assessment Levels in this permit, the permittee shall review the results of all samples collected during the reporting period and report as outlined in Table 5.

6. For parameters with Monthly Average Limits or Monthly Average Assessment Levels in this permit, the permittee shall review the results of all samples collected during the reporting period and report as outlined in Table 6.

Arizona Department of Environmental Quality

Email: AZPDES@azdeq.gov

Arizona Department of Health Services

Attn: Office of Laboratory Licensure and Certification

250 North 17th Avenue

Phoenix, AZ 85007

Table 5. DMR Reporting Requirements for Daily Maximum Limits and Assessment Levels

For Daily Maximum Limits/Assessment Levels The Permittee shall Report on the DMR

When the maximum value of any analytical result is greater than or equal to the LOQ

The maximum value of all analytical results

When the maximum value detected is greater than or equal to the laboratory’s LOD but less than the LOQ

NODI (Q)

When the maximum value is less than the laboratory’s LOD NODI (B)

Table 6. DMR Reporting Requirements for Monthly Average Limits / Assessment Levels

For Monthly Average Limits/Assessment Levels The Permittee shall Report on the DMR

If only one sample is collected during the reporting period (monthly, quarterly, annually, etc.)

(In this case, the sample result is the monthly average.)

When the value detected is greater than or equal to the LOQ The analytical result

When the value detected is greater than or equal to the laboratory’s LOD, but less than the LOQ

NODI (Q)

When the value is less than the laboratory’s LOD NODI (B)

If more than one sample is collected during the reporting period

All samples collected in the same calendar month must be averaged.

• When all results are greater than or equal to the LOQ, all values are averaged

• If some results are less than the LOQ, use the LOD value in the averaging

• Use ‘0’ for values less than the LOD

The highest monthly average which occurred during the reporting period

7. For all field testing, or if the information below is not included on the laboratory reports required by Part

II.B.2, the permittee shall attach a bench sheet or similar documentation to each DMR that includes, for all analytical results during the reporting period the following:

a. the analytical result,

b. the number or title of the approved analytical method, preparation and analytical procedure utilized by the field personnel or laboratory, and the LOD and LOQ for the analytical method for the parameter, and

c. any applicable data qualifiers using the most current revision of the Arizona Data Qualifiers (available online at: http://www.azdhs.gov)

C. Twenty-four Hour Reporting of Noncompliance

1. The permittee shall orally report to the Emergency Response Unit hotline at (602) 771-2330 any noncompliance that poses imminent threat to the environment or human health within 24 hours from the time the permittee becomes aware of the circumstances. The permittee shall also submit an electronic within 5 days of the noncompliance event using the myDEQ electronic portal provided by ADEQ. The permittee shall include in the written notification: a description of the noncompliance and its cause; the period of noncompliance, including dates and times, and, if the noncompliance has not been corrected, the time it is expected to continue; and steps taken or planned to reduce, eliminate, and prevent reoccurrence of the noncompliance.

The following instances of noncompliance are subject to the 24-hour and 5-day reporting requirements and must be reported orally to the Emergency Response Unit hotline:

a. Any unanticipated bypass which exceeds any effluent limitations in the permit,

b. Any upset which exceeds any effluent limitation in the permit, or

c. Any spill or discharge that poses an imminent threat to human health or the environment.

2. All other instances of noncompliance remain subject to the 24-hour and 5-day reporting requirements, and must call the ADEQ AZPDES hotline at (602) 771-1440. For example, an exceedance of any maximum daily limit for the parameters listed in Part 1.A Table 1 that does not poses an imminent threat to human health or the environment.

3. The permittee shall retain records the following monitoring records:

a. Date, exact location and time of sampling or measurements performed, preservatives used;

b. Individual(s) who performed the sampling or measurements;

c. Date(s) the analyses were performed;

d. Laboratory(s) which performed the analyses;

e. Analytical techniques or methods used;

f. Chain of custody forms;

g. Any comments, case narrative or summary of results produced by the laboratory. These comments should identify and discuss QA/QC analyses performed concurrently during sample analyses and should specify whether analyses met project requirements and 40 CFR 136. If results include information on initial and continuing calibration, surrogate analyses, blanks, duplicates, laboratory control samples, matrix spike and matrix spike duplicate results, sample receipt condition, or holding times and preservation, these records must also be retained.

h. Summary of data interpretation and any corrective action taken by the permittee.

PART III. WHOLE EFFLUENT TOXICITY TESTING REQUIREMENTS

A. General Conditions

1. The permittee shall conduct chronic (acute or both) toxicity tests on an 24-hour composite samples of the final effluent at the frequencies specified in Part 1.

2. Final effluent samples must be taken following all treatment processes, including chlorination and dechlorination, and prior to mixing with the receiving water. The required WET tests must be performed on unmodified samples of final effluent. WET tests conducted on samples that are dechlorinated after collection are not acceptable for compliance with this permit.

3. Chemical testing for all the parameters listed in Parts I.A and B of this permit whose required sample type is a composite shall be performed on a split of at least one of the three composite samples taken for one chronic WET test. For those parameters listed in Parts I.A and B of this permit whose required sample type is discrete, the testing shall be performed on a discrete sample collected concurrently with one sample, discrete or composite, collected for an acute or chronic WET test.

4. Definitions related to toxicity are found in Appendix A.

B. Chronic Toxicity

1. The permittee shall conduct short-term chronic toxicity tests on three species: the waterflea, Ceriodaphnia dubia (survival and reproduction test); the fathead minnow, Pimephales promelas (larval survival and growth test); and the green alga, Pseudokirchneriella subcapitata (formerly known as Selenastrum capricornutum or Raphidocelis subcapitata) (growth test).

2. The permittee must follow the USEPA 4th edition manual, “Short-term Methods for Estimating the Chronic

Toxicity of Effluents and Receiving Waters to Freshwater Organisms (EPA/821-R-02-013) for all chronic compliance toxicity testing.

3. The chronic toxicity action levels are any one test result greater than 1.6 Tus or any calculated monthly median value greater than 1.0 TUc. If chronic toxicity is detected above these values, follow-up testing is required per Part IV, Section E. A chronic toxicity unit (TUc) shall be calculated as TUc = 100/NOEC.

4. The chronic WET test shall be conducted using a series of five dilutions and a control. The following dilution series must be used: 12.5, 25, 50, 75, and 100% effluent.

C. Quality Assurance

1. Effluent samples must be maintained between 0 and 6°C from collection until utilized in the toxicity testing procedure. When a composite sample is required, each aliquot making up the composite must be chilled after collection and throughout the compositing period. The single allowable exception is when a grab sample is delivered to the performing laboratory for test initiation no later than 4 hours following the time of collection.

2. Control and dilution water should be receiving water or lab water as appropriate, as described in the 40 CFR

Part 136.3 approved method. If the dilution water used is different from the culture water, a second control, using culture water shall also be used.

3. Reference toxicity tests, (a check of the laboratory and test organisms’ performance), shall be conducted at least 1 time in a calendar month for each toxicity test method conducted in the laboratory during that month. Additionally, any time the laboratory changes its source of test organisms, a reference toxicity test must be conducted before or in conjunction with the first WET test performed using the organisms from the newer source. Reference toxicant testing must be conducted using the same test conditions as the effluent toxicity tests (ie., same test duration, etc.).

4. If either the reference toxicant test or the effluent test does not meet all test acceptability criteria as specified in the 40 CFR Part 136.3 approved WET methods, then the permittee must re-sample and re-test within 14 days of receipt of the test results. The re-sampling and re-testing requirements include laboratory induced error in performing the test method.

5. The chronic reference toxicant and effluent tests must meet the upper and lower bounds on test sensitivity as determined by calculating the percent minimum significant difference (PMSD) for each test result. The test sensitivity bound is specified for each test method (see Section 10, Table 6 in EPA/821-R-02-013). There are five possible outcomes based on the PMSD result.

a. Unqualified Pass- The test’s PMSD is within bounds and there is no significant difference between the means for the control and the effluent. The regulatory authority would conclude that there is no toxicity.

b. Unqualified Fail- The test’s PMSD is larger than the lower bound (but not greater than the upper bound) in Table 6 and there is a significant difference between the means for the control and the effluent. The regulatory authority would conclude that there is toxicity.

c. Lacks Test Sensitivity- The test’s PMSD exceeds the upper bound in Table 6 and there is no significant difference between the means for the control and the effluent. The test is considered invalid. An effluent sample must be collected and another toxicity test must be conducted within 14 days of receipt of the test results.

d. Lack Test Sensitivity- The test’s PMSD exceeds the upper bound in Table 6 and there is a significant difference between the means for the control and the effluent. The test is considered valid. The regulatory authority will conclude that there is toxicity.

e. Very Small but Significant Difference- The relative difference between the means for the control and effluent is smaller than the lower bound in Table 6 and this difference is statistically significant. The test is acceptable and the NOEC should be determined.

D. Toxicity Identification Evaluation (TIE)/Toxicity Reduction Evaluation (TRE) Process

1. If chronic toxicity is detected above a WET action level or Limit specified in this permit and the source of toxicity is known (for instance, a temporary plant upset), the permittee shall conduct one follow-up test within two weeks of receipt of the sample results that exceeded the action level. The permittee shall use the same test and species as the failed toxicity test. For intermittent discharges, the follow-up test shall be conducted whether discharging or not. If toxicity is detected in the follow-up, the permittee shall immediately begin developing a TRE plan and submit the plan to ADEQ for review and approval within 30 days after receipt of the toxic result. Requirements for the development of a TRE are listed in paragraph 3 below. The permittee must implement the TRE plan as approved and directed by ADEQ.

2. If chronic toxicity is detected above an action level or Limit specified in this permit and the source of toxicity is unknown, the permittee shall begin additional toxicity monitoring within two weeks of receipt of the sample results that exceeded the action level. The permittee shall conduct one WET test approximately every other week until either a test exceeds an action level (or limit) or four tests have been completed. The follow-up tests must use the same test and species as the failed toxicity test. For intermittent discharges, the first follow-up test shall be conducted whether discharging or not; the subsequent three follow-up tests shall be conducted during the next three discharge events.

a. If none of the four tests exceed a WET action level or limit, then the permittee may return to the routine WET testing frequency specified in this permit.

b. If a WET action level or limit is exceeded in any of the additional tests, the permittee shall immediately begin developing a TRE plan and submit the plan to ADEQ for review and approval within 30 days after receipt of the toxic result. Requirements for the development of a TRE are listed in subsection 3, below. The permittee must implement the TRE plan as approved and directed by

ADEQ.

a. The permittee shall use the EPA guidance manual Toxicity Reduction Evaluation Guidance for

Municipal Wastewater Treatment Plants, 1999 (EPA/833/B-99/002) in preparing a TRE plan. The TRE plan shall include, at a minimum, the following: Further actions to investigate and identify the causes of toxicity, if unknown. The permittee may initiate a TIE as part of the TRE process using the following EPA manuals as guidance: Toxicity Identification Evaluation: Characterization of Chronically

Toxic Effluents, Phase I, 1992 (EPA/600/6-91/005F); Methods for Aquatic Toxicity Identification

Evaluations: Phase I, Toxicity Characterization Procedures, 2nd Edition, 1991 (EPA/600/6-91/003);

Methods for Aquatic Toxicity Identification Evaluations: Phase II, Toxicity Identification Procedures for Samples Exhibiting Acute and Chronic Toxicity, 1993 (EPA/600/R-92/080); and Methods for

Aquatic Toxicity Identification Evaluations: Phase III, Toxicity Confirmation Procedures for Samples

Exhibiting Acute and Chronic Toxicity, 1993 (EPA/600/R-92/081).

b. Action the permittee will take to mitigate the impact of the discharge and to prevent the recurrence of toxicity; and

c. A schedule for implementing these actions.

E. WET Reporting

1. The permittee shall report chronic toxicity results on DMRs in Chronic Toxicity Units (TUc). The TUc for DMR reporting shall be calculated as TUc= 100/NOEC.

2. In addition to reporting WET results on DMRs, the permittee shall submit a copy of the full lab report(s) for all WET testing conducted during the monitoring period covered by the DMR. The lab report should report TUc as 100/NOEC and as 100/IC25. If the lab report does not contain any of the following items, then these must also be supplied in a separate attachment to the report: 1) sample collection and test initiation dates,

2) the results of the effluent analyses for all parameters required to be tested concurrently with WET testing as defined in Part I.A and B, Tables 1 and 2, and Part IV.A.3 of this permit, and 3) copies of completed “AZPDES Discharge Flow Records” for the months in the WET monitoring period.

3. WET lab reports and any required additional attachments shall be submitted to ADEQ by the 28th day of the month following the end of the WET monitoring period, or upon request.

PART IV. SPECIAL CONDITIONS

A. Operation

The permittee shall ensure that the facilities or systems are operated by or under the supervision of an operator currently certified by ADEQ at the level appropriate for the facility or system.

B. Mixing Zone Conditions

A mixing zone for copper was granted with a majof modification in 2019 for the duration of the 2017 permit. At that time, ADEQ evaluated the request and approved establishment of the copper mixing zone. The factors in Arizona mixing zones rules listed in A.A.C. R18-11-114(D) were considered upon approving the request. The permittee shall submit a complete mixing zone application for this 2022 permit within one year of issuance of this permit and shall continue to monitor and report for copper as required for effluent characterization.

C. Reopener

1. This permit may be modified per the provisions of A.A.C. R18-9-B906, and R18-9-A905 which incorporates

40 CFR Part 122. This permit may be reopened based on newly available information; to add conditions or limits to address demonstrated effluent toxicity; to implement any EPA-approved new Arizona water quality standard; or to re-evaluate reasonable potential (RP), if Assessment Levels in this permit are exceeded.

Appendix A. Part A: Acronyms

A.A.C. Arizona Administrative Code ADEQ Arizona Department of Environmental Quality ADHS Arizona Department of Health Services EQ Exceptional Quality (biosolids) AZPDES Arizona Pollutant Discharge Elimination System A.R.S. Arizona Revised Statutes CFR Code of Federal Regulations CFU Colony Forming Units Director The Director of ADEQ or any authorized representative thereof DMR Discharge Monitoring Report EPA The U.S. Environmental Protection Agency kg/day Kilograms per day MGD Million Gallons per Day mg/L Milligrams per Liter, also equal to parts per million (ppm) MPN Most Probable Number NPDES National Pollutant Discharge Elimination System PFU Plaque-Forming Unit QA Quality Assurance SSU Sewage Sludge Unit TBEL Technology-based Effluent Limitation µg/L Micrograms per Liter, also equal to parts per billion (ppb) WQBEL Water quality-based Effluent Limitation

Appendix A. Part B: Definitions

Acute Toxicity Test

A test used to determine the concentration of effluent or ambient waters that produces an adverse effect (lethality) on a group of test organisms during a short-term exposure 9e.g., 24, 48, or 96 hours). Acute toxicity is measured using statistical procedures (e.g., pint estimate techniques or hypothesis testing) and is reported as PASS/FAIL or in TUas, where TUa =

100LC50.

Acute-to Chronic Ratio (ACR)

Is the ratio of the acute toxicity of an effluent or a toxicant to its chronic toxicity. It is used as a factor for estimating chronic toxicity on the basis of acute toxicity data, or for estimating acute toxicity on the basis of chronic toxicity data.

Agronomic Rate

The whole biosolids application rate on a dry-weight basis that meets the following conditions: a.) The amount of nitrogen needed by existing vegetation or a planned or actual crop has been provided, and b.) The amount of nitrogen that passes below the root zone of the crop or vegetation is minimized.

Ammonia Impact Ratio (AIR) The ratio of the concentration of ammonia in the effluent and the calculated ammonia standard as determined by the use of effluent/receiving water pH and temperature.

Annual Pollutant Loading Rate The maximum amount of a pollutant that can be applied to an acre or hectare of land during a 365-day period.

Applicator A person who arranges for and controls the site-specific land application of biosolids in Arizona.

Base Flood A flood that has a one percent chance of occurring in any given year (or a flood that is likely to occur once in 100 years).

Bulk Biosolids Biosolids that are transported and land-applied in a manner other than in a bag or other container holding biosolids of 1.102 short tons or 1 metric ton or less.

Chronic Toxicity Test

A test in which sublethal effects (e.g., reduced growth or reproduction) are measured in addition to lethality. Chronic toxicity is measured as TUc = 100/NOEC or TUc = 100/Ecp or 100/ICp. The ICp and ECp value should be the approximate equivalent of the NOEC calculated by hypothesis testing for each test method.

Composite Sample

A sample that is formed by combining a series of individual, discrete samples of specific volumes at specified intervals. Composite samples characterize the quality of a discharge over a given period of time.Although, composite samples can be time-weighted or flow-weighted, this permit requires the collection of flow-proportional composite samples. This means that samples are collected and combined using aliquots in proportion to flow rather than time. Also see Flow- Proportional Composite.

Cumulative Pollutant Loading Rate The maximum amount of a pollutant applied to land application site.

Daily Maximum Concentration Limit The maximum allowable discharge of a pollutant in a calendar day as measured on any single discrete sample or composite sample.

Daily Maximum Mass Limit The maximum allowable total mass of a pollutant discharged in a calendar day.

Discrete or Grab Sample An individual sample of at least 100 mL collected from a single location, or over a period of time not exceeding 15 minutes.

Dry-Weight Basis The weight of biosolids calculated after the material has been dried at 105 ˚C until reaching a constant mass.

Effect Concentration Point (ECP)

A point estimate of the toxicant (or effluent) concentration that would cause an observable adverse effect (e.g., survival or fertilization) in a given percent of the test organisms, calculated from a continuous model (e.g., USEPA Probit Model).

Effluent Dependent Water Effluent Dependent Water means a surface water or portion of a surface water that consists of a point source discharge without which the surface water would be ephemeral. An effluent dependent water may be perennial or intermittent depending on the volume and frequency of the point source discharge of treated wastewater.

Ephemeral Water Ephemeral water means a surface water or portion of surface water that flows or pools only in direct response to precipitation.

Flow Proportional Composite Sample

A sample that combines discrete samples collected over time, based on the flow of the discharge being sampled. There are two methods used to collect this type of sample. One collects a constant sample volume at time intervals that vary based on stream flow. The other collects discrete samples that are proportioned into aliquots of varying volumes based on stream flow, at constant time intervals (i.e. flow-weighted composite sample).

Hardness The sum of the calcium and magnesium concentrations, expressed as calcium carbonate (CACO3) in milligrams per liter.

Hypothesis Testing

A statistical technique (e.g., Dunnetts test) that determines what concentration is statistically different from the control. Endpoints determined from hypothesis testing are NOEC and LOEC. The two hypotheses commonly tested in WET are:

Null hypothesis (H0): The effluent is not toxic.

Alternative hypothesis (Ha): The effluent is toxic.

Impaired Water

Impaired water means a protected surface water for which credible scientific data exists that satisfies the requirements of section 49-232, and that, in the case of waters of the U.S., demonstrate that the water should be identified pursuant to 33 United States Code section 1313(d) and the regulations implementing that statute

Inhibition Concentration (IC)

A point estimate of the toxicant concentration that would cause a given percent reduction in a non-lethal biological measurement (e.g., reproduction or growth) calculated from a continuous model (e.g., USEPA Interpolation Method). IC25 is a point estimate of the toxicant concentration that would cause a 25% reduction in a non-lethal biological measurement.

Intermittent Water

Intermittent water means a surface water or portion of surface water that flows continuously during certain times of the year and more than in direct response to precipitation, such as when it receives water from a spring, elevated groundwater table or another surface source such as melting snowpack.

Land Treatment Facility

An operation designed to treat and improve the quality of waste, wastewater, or both, by placement wholly or in part on the land surface to perform part or all of the treatment. A land treatment facility includes a facility that performs biosolids drying, processing, or composting, but not land application performed in compliance with 18 A.A.C. 9, Article 10.

LC50

The toxicant (or effluent) concentration that would cause death in 50 percent of the test organisms.

Limit of Quantitation (LOQ)

The minimum levels, concentrations, or quantities of a target variable such as an analyte that can be reported with a specific degree of confidence.The calibration point shall be at or below the LOQ. The LOQ is the concentration in a sample that is equivalent to the concentration of the lowest calibration standard analyzed by a specific analytical procedure, assuming that all of the method-specified sample weights, volumes, and processing steps have been followed.

Limit of Detection (LOD)

An analyte and matrix-specific estimate of the minimum amount of a substance that the analytical process can reliably detect with a 99% confidence level. This may be laboratory dependent and is developed according to R9014-615(C)(7).

Method Detection Limit (MDL) See LOD

Mixing Zone

An area where an effluent discharge undergoes initial dilution and may be extended to cover the secondary mixing in the ambient waterbody. A mixing zone is an allocated impact zone where water quality criteria can be exceeded as long as acutely toxic conditions are prevented.

Monthly or Weekly Average Concentration Limit

Other than for bacteriological testing, means the highest allowable average calculated as an arithmetic mean of consecutive measurements made during calendar month or week, respectively. The "monthly or weekly average concentration limit” for E. coli bacteria means the highest allowable average calculated as the geometric mean of a minimum of four

(4) measurements made during a calendar month or week, respectively.

The geometric mean is the nth root of the product of n numbers. For either method (CFU or MPN), when data are reported as “0” or non-detect then input a “1” into the calculation for the geometric mean.

No Observed Effect Concentration

(NOEC)

The highest tested concentration of effluent or toxicant, that causes no observable adverse effect on the test organisms (i.e., the highest concentration of toxicant at which the values for the observed responses are not statistically significant different from the controls).

Pathogen A disease-causing organism.

Point Estimate Techniques

As Probit, Interpolation Method, Spearman-Karber are used to determine the effluent concentration at which adverse effects (e.g., fertilization, growth or survival) occurred. For example, concentration at which a 25 percent reduction in fertilization occurred.

Point Source

Point Source means any discernible, confined and discrete conveyance, including, any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling stock, concentrated animal feeding operation or vessel or other floating craft from which pollutants are or may be discharged to a protected surface water. Point source does not include return flows from irrigated agriculture.

Protected Surface Waters Protected Surface Waters means waters of the State listed on the protected surface water list under Section 49-221, Subsection G and all

WOTUS.

Publicly owned treatment works Publicly owned treatment works" means a treatment works owned by this state or a municipality of this state as defined in section 502(4) of the clean water act or that discharges to a protected surface water.

Reference Toxicant Test

A toxicity test conducted with the addition of a known toxicant to indicate the sensitivity of the organisms being used and demonstrate a laboratory’s ability to obtain consistent results with the test method. Reference toxicant data are part of the routine QA/QC program to evaluate the performance of laboratory personnel and test organisms.

Runoff Rainwater, leachate, or other liquid that drains over any part of a land surface and runs off of the land surface.

Sewage Sludge Unit Land on…