91ST rd Ave. Wastewater Treatment Plant Toxicity ......91ST Ave./23rd Ave. Wastewater Treatment...

WATER SERVICES DEPARTMENT

91ST Ave./23rd Ave. Wastewater Treatment Plant

Toxicity Identification Evaluation (T.I.E.) Professional Services

PROJECT NOs. WS90100103 and WS90200023

NOTIFICATION LETTER #1

August 16, 2016 This notification letter shall become a part of the Request for Qualifications for the above referenced project. The attached document entitled “City of Phoenix / 91st Avenue Wastewater Treatment Plant / Toxicity Reduction/Toxicity Identification Evaluation / Workplan dated July 2012 is included at Exhibit “A” to the Request for Qualifications (RFS) referenced above.

Donna Wiltshire Contract Specialist CITY OF PHOENIX DESIGN AND CONSTRUCTION PROCUREMENT

CCiittyy ooff PPhhooeenniixx OFFICE OF THE CITY ENGINEER

DESIGN AND CONSTRUCTION PROCUREMENT 200 West Washington Street, 6th Floor

Phoenix, Arizona 85003-1611

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CITY OF PHOENIX

91st AVENUE WASTEWATER TREATMENT PLANT

TOXICITY REDUCTION /TOXICITY IDENTIFICATION EVALUATION WORKPLAN

TABLE OF CONTENTS

Page

List of Tables .............................................................................................................. iii List of Figures ............................................................................................................. iii List of Abbreviations ................................................................................................... iv

SECTION I INTRODUCTION ..................................................................................... I-1

SECTION II PERMIT REQUIREMENTS ..................................................................... II-1 Limitations and Monitoring Requirements for Conventional Parameters .................... II-1 Whole Effluent Toxicity Testing Requirements ............................................................ II-1 Accelerated Whole Effluent Toxicity Testing ............................................................... II-3

SECTION III PLANT DESCRIPTION .......................................................................... III-1

SECTION IV RESPONSIBILITIES FOR RESPONSE ACTIONS FOR TOXICITY REDUCTION EVALUATION-RELATED STUDIES ............................................... IV-1

SECTION V PROTOCOLS FOR SAMPLING AND ANALYSES FOR ACCELERATED TESTING AND TOXICITY REDUCTION EVALUATION ...................................... V-1

Sample Collection and Transport to Water Services Laboratory ................................. V-1 Chain-of-Custody Forms ............................................................................................. V-1 Chemical Analyses ...................................................................................................... V-1 Sample Storage ........................................................................................................... V-2 Sample Shipment to AECOM ...................................................................................... V-2

SECTION VI ACCELERATED TESTING PHASE ....................................................... VI-1 Notification Procedures ............................................................................................... VI-1 Split samples ............................................................................................................... VI-1 Activities In Response to Notification of Toxicity ......................................................... VI-1 Activities in Response to WET Test Exhibiting Toxicity During Accelerated Testing .. VI-4

Development of Detailed Workplan ...................................................................... VI-4 Initiation of TIE Studies ......................................................................................... VI-5

SECTION VII TOXICITY IDENTIFICATION AND REDUCTION EVALUATIONS ....... VII-1 Objectives .................................................................................................................... VII-1 Approach ..................................................................................................................... VII-1

Toxicity Identification Evaluation .......................................................................... VII-3 Phase I Toxicant Characterization .................................................................... VII-3 Phase II Toxicant Identification ......................................................................... VII-7 Phase III Toxicant Confirmation ........................................................................ VII-9

Toxicant Source Identification .............................................................................. VII-9 Toxicity Control Evaluation ................................................................................... VII-10

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CITY OF PHOENIX

91st AVENUE WASTEWATER TREATMENT PLANT

TOXICITY REDUCTION /TOXICITY IDENTIFICATION EVALUATION WORKPLAN

TABLE OF CONTENTS

Page

Termination of TRE ..................................................................................................... VII-10 EPA Coordination ........................................................................................................ VII-10 Reports ........................................................................................................................ VII-11 Schedule ..................................................................................................................... VII-11

APPENDICES

Appendix A-1 91st Avenue WWTP Flow Schematic

Appendix A-2 Tres Rios Wetland Flow Schematic and Site Plan

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LIST OF TABLES

No. Description Page

II-1 Effluent Limitations for Conventional Parameters .................................................. II-2

IV-1 Key Personnel ........................................................................................................ IV-3

VI-1 Senior Review Team .............................................................................................. VI-4

VII-1 Examples of Toxicants Removed by Toxicant Characterization Tests .................. VII-5

LIST OF FIGURES

No. Description Page

IV-1 Organization Chart ................................................................................................. IV-2

VI-1 Actions Following Test Failure During Accelerated Testing ................................... VI-2

VII-1 Toxicity Reduction Evaluation Flow Chart .............................................................. VII-2

VII-2 Toxicity Characterization Protocol .......................................................................... VII-6

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LIST OF ABBREVIATIONS

91st Ave WWTP 91st Avenue Wastewater Treatment Plant

ADEQ Arizona Department of Environmental Quality

AECOM AECOM Fort Collins Environmental Toxicology Laboratory

ANPP Arizona Nuclear Power Project

APAI Alan Plummer Associates, Inc.

C. dubia Ceriodaphnia dubia

cfu colony forming units

City City of Phoenix

C degrees Centigrade

Dept department

DMR Discharge Monitoring Report

DO dissolved oxygen

EMS Environmental Monitoring Section

EPA U. S. Environmental Protection Agency

ESD Environmental Services Division

FRW Flow Regulating Wetland

GC-MS gas chromatography/mass spectroscopy

GRIC Gila River Indian Community

HDW Hayfield Demonstration Wetlands

HPLC High Performance Liquid Chromatography

L liter

LSS Laboratory Services Section

mg/L milligrams per liter

MGD million gallons per day

ml milliliter

NOEC No Observed Effect Concentration

NPDES National Pollutant Discharge Elimination System

P. promelas Pimephales promelas

PCD Pollution Control Division

PVNGS Palo Verde Nuclear Generating Station

QA Quality Assurance

S. capricornutum Selenastrum capricornutum

SPE solid-phase extraction

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LIST OF ABBREVIATIONS (Continued)

SROG Sub-Regional Operating Group

STRs Salinity/Toxicity Relationships

TDS total dissolved solids

TIE Toxicity Identification Evaluation

TRE Toxicity Reduction Evaluation

TUc toxic units, chronic

ug/L micrograms per liter

UP01 Unified Plant 2001

UP05 Unified Plant 2005

WET Whole Effluent Toxicity

WWO Wastewater Operations

WSD Water Services Department

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SECTION I

INTRODUCTION

The 91st Avenue Wastewater Treatment Plant (91st Ave WWTP) includes the Tres Rios Flow

Regulating Wetland (FRW) and Hayfield Demonstration Wetlands (HDW). The 91st Avenue

WWTP is regulated by the National Pollutant Discharge Elimination System (NPDES) permits

issued by the U.S. Environmental Protection Agency. The permit number is AZ0020524 and

expires June 30, 2015.

Per the NPDES permit, final effluent samples are required to be collected at outfall 001 and at

outfall 005 to conduct chronic whole effluent toxicity (WET) tests. Outfall 001 consists of effluent

from the traditional wastewater treatment from the 91st Avenue WWTP whereas outfall 005 is

effluent from the Tres Rios FRW. Currently, effluent is not discharged from the HDW and there

are no WET test requirements at this location. A WET test exhibiting effects above a discharge

limit or action level specified in the permit triggers an accelerated toxicity testing program. A

WET test exhibiting significant toxicity during accelerated testing results in the initiation of a

toxicity reduction evaluation (TRE). The permit also specifies that a TRE plan be submitted to

EPA for review within 14 days after receipt of a WET test exhibiting toxicity during accelerated

testing.

This document has been prepared to serve as a draft TRE workplan to be finalized if a WET test

exhibiting toxicity requires the initiation of a TRE. The draft workplan has been developed jointly

by the City Water Services Department (WSD) and Alan Plummer Associates, Inc. (APAI).

This workplan will be finalized, as appropriate, if a WET test result triggers a TRE.

The accelerated testing program required by the permit is not part of a TRE. However, actions

may be performed in conjunction with the accelerated testing program that could enhance the

City’s ability to successfully complete the TRE in a timely manner. In addition, many of the

protocols for communication, coordination, and sample management that will be important

during the TRE are also applicable during the accelerated testing phase. Therefore, this

workplan addresses both the accelerated testing program and the TRE.

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SECTION II

PERMIT REQUIREMENTS

The 91st Ave WWTP is located on the north bank of the Salt River, in Tolleson, Arizona. The

associated Tres Rios FRW is located west and south of the facility. The facility provides

wastewater treatment services for the Sub-Regional Operating Group (SROG) member cities of

Glendale, Mesa, Phoenix, Scottsdale, and Tempe, in Maricopa County, Arizona.

The 91st Ave WWTP employs a nitrification/denitrification process to treat municipal and

industrial wastewater generated in the metropolitan Phoenix area. As a result of recent

expansion and upgrades the current treatment plant design capacity is 230 million gallons per

day (MGD). Approximately 45 MGD is pumped to the Tres Rios FRW.

LIMITATIONS AND MONITORING REQUIREMENTS FOR CONVENTIONAL PARAMETERS

The effluent limitations and monitoring requirements are based on a design capacity of 230

MGD Permit limitations for select conventional parameters are presented in Table II-1.

WHOLE EFFLUENT TOXICITY TESTING REQUIREMENTS

The permit requires WET tests using the water flea, Ceriodaphnia dubia (C. dubia), the fathead

minnow, Pimephales promelas (P. Promelas) and green algae, Selenastrum capricornutum

(S. capricornutum). The permit specifies a monthly testing frequency for C. dubia. The P.

Promelas and S capricornutum, monitoring frequency is quarterly. Chemical testing for all

parameters listed in Table 1 of the permit are performed concurrently with the quarterly WET

testing of all three species.


TABLE II-1

City of Phoenix Toxicity Reduction Evaluation Workplan

91st Avenue Wastewater Treatment Plant

Effluent Limitations for Conventional Parameters*

Permitted Concentration

Constituent Monthly Average

Weekly Average

Daily Maximum

Monitoring Frequency

Sample Type

Flow (2) (2) (2) Continuous Metered

Carbonaceous Biochemical Oxygen Demand (5-day)

25 mg/L 40 mg/L (1) Daily 24 Hour

Composite

E coli 126 cfu/100 ml ------ 575 cfu/100 ml Daily Discrete

Total Suspended Solids

30 mg/L 45 mg/L (1) Daily 24 hour

Composite

Total Residual Chlorine

11 ug/L ------ 18.1 ug/L Daily Discrete

pH Not less than 6.5 nor greater than 9.0 Daily Discrete (1)

NA = Not Applicable (2)

Monitoring and reporting required. No limit is set. * Outfall Number 001, 002, and 005.

The WET tests are to be performed on unmodified samples of final effluent using five effluent

dilutions specified in the permit, these dilutions are 100%, 62.5%, 50%, 25% and 12.5%. WET

is measured by determining which concentration of effluent exhibits no significant effect. The

permit defines the No Observed Effect Concentration (NOEC) as the highest concentration of

effluent or toxicant that causes no observable adverse effect on the test organisms. Results of

the WET tests are reported in terms of chronic toxicity units (TUc) and are defined as follows:

TUc = 100/NOEC

C. dubia has a chronic toxicity effluent limit and P promelas and S capricornutum have action

levels. The chronic toxicity effluent limit and action levels are a monthly median value greater

than 1.0 TUc and any single test with a value greater than 1.6 TUc. WET test results reported

above the effluent limit or action level require initiation of accelerated testing.


ACCELERATED WHOLE EFFLUENT TOXICITY TESTING

The permit stipulates the initiation of accelerated testing within two weeks of receipt of results

exceeding an effluent limit or action level. If toxicity, as defined above, is exhibited in any of the

accelerated tests, a TRE must be initiated.

If the cause of the WET test failure is known, such as a temporary plant upset, then only one

additional test using the same species and test method is required to be initiated within 14 days

of receipt of the test results. If the cause of the WET test failure is not known then the

exceedance triggers six additional toxicity tests using the same species and test method and

scheduled approximately every two weeks over a 12-week period.

The City can resume the regular testing frequency if none of the additional WET tests exceed

the chronic WET effluent limit or action level. If one of the additional toxicity tests exceeds the

WET effluent limit or action level then the City is required to initiate a TRE.

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SECTION III

PLANT DESCRIPTION

The 91st Ave WWTP utilizes a nitrification/denitrification process to treat municipal and

industrial wastewater. The facility consists of multiple process trains, including the older Plants

1, 2 and 3, which are operated in parallel that merge before chlorination / dechlorination and the

Unified Plant 2001 (UP01) and Unified Plant 2005 (UP05), with process units that are flexible

and interchangeable dictated by operational and maintenance needs.. A flow schematic is

presented in Appendix A.

In general the plants include the following unit processes: screening, grit removal, flow

measurement/flow distribution, primary sedimentation (with enhanced sedimentation possible),

activated sludge biological treatment, secondary clarification, chlorine disinfection, centrifuge

thickening of primary sludge and waste activated sludge, anaerobic sludge digestion, sludge

drying beds, and centrifuge dewatering of digested sludge.

Effluent from the 91st Avenue WWTP can be conveyed to the Palo Verde Nuclear Generating

Station (PVNGS) via the Arizona Nuclear Power Project (ANPP) pipeline, to the Tres Rios FRW

before discharge to the Salt River, or directly to the Salt River.

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SECTION IV

RESPONSIBILITIES FOR RESPONSE ACTIONS FOR

TOXICITY REDUCTION EVALUATION-RELATED STUDIES

The activities required in response to a trigger for a TRE will be accomplished by the joint efforts

of the City, APAI, and AECOM Fort Collins Environmental Toxicology Laboratory (AECOM). An

organizational chart of key personnel associated with the TRE is presented in Figure IV-1. Table

IV-1 presents the respective responsibilities, telephone and fax numbers, mailing addresses,

and e-mail addresses.

The responsibilities of the respective groups are as follows:

The City will be responsible for the direction and coordination of the project, liaison

with EPA, ADEQ, and the Gila River Indian Community (GRIC), sampling, chemical

analyses, routine monthly biomonitoring, and accelerated toxicity testing.

AECOM will be responsible for the TRE/TIE analytical work.

APAI will coordinate TRE activities, prepare sampling plans, prepare periodic and

final reports, and initiate conference calls.

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Table IV -1 City of Phoenix

Toxicity Reduction Evaluation Workplan

91st Avenue Wastewater Treatment Plant Key Personnel

Name

Organization Role

Telephone Addresses

Voice Fax Mailing E-mail

Jennifer Calles City of Phoenix Water Services Department Environmental Services Division Laboratory Services

QA review of analytical and WET analytical results.

602-256-5658 602-534-7151 Water Services Dept. Building 31 2474 South 22nd Ave. Phoenix AZ 85009

[email protected]

Andrea Cooper City of Phoenix Water Services Department Environmental Services Division Environmental Monitoring

Wastewater Monitoring Group


[email protected]

Ron Elkins City of Phoenix Water Services Department Tres Rios Wetlands

Provide information on Tres Rios activities and conditions that may be relevant to the TRE.

602-495-7766 602-495-7999 91st Avenue WWTP 5615 S 91st Avenue Tolleson, AZ 85353

[email protected]

David Epperson Kathi Barrett to be included as a contact for 91

st Ave

Process Control Specialist (Solids) - 91

st Avenue

WWTP

Provide information on plant activities and conditions that may be relevant to TRE.

602-534-6918 602-495-7999 91st Avenue WWTP 5615 S 91st Avenue Tolleson, AZ 85353

[email protected]

Kris Erickson City of Phoenix Water Services Department Environmental Services Environmental Monitoring

Assistant to the Water Superintendent

602-495-7477 602-534-7151 Water Services Department 2474 South 22nd Avenue Building 31 Phoenix, AZ 85009

[email protected]

Debbie Sue Estrada City of Phoenix Water Services Department Environmental Services Division Environmental Monitoring

Regulatory/Technical contact for activities associated with the 91

st

Avenue Wastewater Treatment Plant.


[email protected]

Behrouz Fathali Wastewater Engineering Project Manager for City of Phoenix; project administrative issues

602-262-4597 200 W. Washington Street 8

th Floor

Phoenix, AZ 85003

[email protected]

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me Organization Role

Telephone Addresses

Voice Fax Mailing E-mail

Heather Finden City of Phoenix Water Services Department Environmental Services Environmental Monitoring

Regulatory/Technical contact for activities associated with the 23

rd

Avenue WWTP, Cave Creek Water Reclamation Plant and Rio Salado Habitat Restoration Project.


[email protected]

Peggy W. Glass, Ph.D. *

Alan Plummer Associates, Inc.

Technical Liaison 512-452-5905 512-452-2325 6300 La Calma Suite 400 Austin TX 78752

[email protected]

Randy A. Gottler* City of Phoenix Water Services Dept. Environmental Services Division

Water Services Deputy Director – Environmental Services Division


[email protected]

Robert Hollander *

Alan Plummer Associates, Inc.

APAI Project Manager. 480-371-0015 480-264-0678 PMB # 395 7650 S. McClintock Drive, Ste. 103 Tempe, AZ 85284

[email protected]

Rex Hunt Alan Plummer Associates, Inc.

APAI Principal-In-Charge

512.452.5905 512.452.2325 6300 La Calma Suite 400 Austin TX 78752

[email protected]

Chris Pasch * Alan Plummer Associates, Inc.

APAI Technical Lead 512-452-5905 512-452-2325 6300 La Calma Suite 400 Austin TX 78752

[email protected]

Rami Naddy * AECOM Technical Services, Inc.

Direction of TIE and TRE laboratory studies; contact point for coordination when effluent samples are shipped to AECOM for TRE study and when TRE samples are sent back to City for chemical analysis

970-416-0916 Extension 312

(970) 490-2963 4303 West La Porte Ave. Ft. Collins CO 80521

[email protected]

Larry Westerman Process Control Specialist - 91st Avenue WWTP

Provide information on plant activities and conditions that may be relevant to the TRE.

602-534-2349 91st Avenue WWTP 5615 S 91st Avenue Tolleson, AZ 85353

[email protected]

* Member of Senior Review Team

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SECTION V

PROTOCOLS FOR SAMPLING AND ANALYSES

FOR ACCELERATED TESTING AND TOXICITY REDUCTION EVALUATION

This section addresses how samples will be collected and managed during the periods of

accelerated testing and a TRE.

SAMPLE COLLECTION AND TRANSPORT TO WATER SERVICES LABORATORY

Sampling during accelerated testing will follow the same protocol as for routine sampling but will

not include the parameters from Table 1 of the permit. Samples will be collected using

refrigerated designated automatic samplers with new Teflon-lined suction tubing and silicon

pump tubing. All equipment used to collect and prepare composite samples should be carefully

cleaned and rinsed. Once the 24 hour sampling event has concluded, samples will be removed

from the autosampler and stored in the compliance refrigerator to temperature between 1 and 6

degrees Centigrade (ºC). Additional sample volume will be collected to allow for splitting the

samples and WET testing in two laboratories if requested by the City. Samples are transported

from 91st Avenue WWTP compliance refrigerator by courier to the 23rd Avenue Compliance

Laboratory. City staff will arrange for shipping to the contracted laboratory.

CHAIN-OF-CUSTODY FORMS

The City chain-of-custody form will be prepared for each sample. This form will also accompany

any samples sent to the contracted lab and any samples sent by a contracted lab to the City for

chemical analyses. Any unusual conditions or malfunctions that occur during sampling will be

noted on the chain-of-custody form.

CHEMICAL ANALYSES

Chemical analyses should use EPA approved methods to extent possible. In some cases, it

may not be possible to quantify or identify a pollutant with approved methods. If this is

necessary, the laboratory should report the method and equipment used to conduct the

analyses. The City should follow the monitoring and reporting requirements of Part II.B. of the

Permit.

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SAMPLE STORAGE

WET testing will be performed by the City’s contract laboratory Bio-Aquatic Testing Inc.

(BioAquatic), or by AECOM. Only the portion of the sample used for the test and the pretest

chemical characterization will be removed from the sample storage container and warmed to

room temperature. The remaining portion will be stored at 1-6ºC in the original storage

container. APAI and the laboratories will coordinate and determine when samples can be

discarded.

SAMPLE SHIPMENT TO AECOM

No more than one 5-gallon container will be placed in a 48-quart ice chest. The sample

container, and sufficient bagged ice to fill the remaining space, will be placed in the ice chest.

The bagged ice will be sealed to prevent leakage. The total weight of this ice chest may exceed

75 pounds; therefore, a “Caution – Very Heavy Item” sticker should be placed on the ice chest.

Proper chain-of-custody forms will be prepared and attached to the shipment. The samples will

be shipped via overnight delivery to the laboratory.

Samples should not be shipped on a Saturday, to avoid weekend-delayed delivery, unless

Sunday delivery can be confirmed by the carrier.

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SECTION VI

ACCELERATED TESTING PHASE

The topics discussed in this section are notification procedures, actions to be taken in response

to the notification of a routine WET test exhibiting significant toxicity, and actions to be taken in

the event of a WET test exhibiting toxicity during accelerated testing.

NOTIFICATION PROCEDURES

The permit stipulates that accelerated testing must begin within two weeks of receipt of routine

WET test results indicating significant toxicity. Timing, with respect to the permit requirements,

begins when the City receives the routine test laboratory reports demonstrating exceedance of

the permit limit or action level.

SPLIT SAMPLES

It is not unusual for the effluent to exhibit sporadic sublethal effects in the C. dubia WET test.

The sporadic effects can be a result of changing organism response in the laboratory. Split

sample analyses can help in determining whether WET test failures are attributable to the

condition of the organisms in the laboratory culture or another cause.

If accelerated testing is triggered by a WET test failure in the C. dubia test, samples may be split

and shipped to both BioAquatic and AECOM for WET testing. Both laboratories will conduct

WET tests following procedures consistent with the discharge permit. Differing results between

the laboratories, one reporting a WET test failure and the other a pass, would likely indicate that

initiating a TRE may not be an appropriate response. If the City decides to split samples, close

coordination with the staff will be required to ensure that sufficient sample can be collected for

two laboratories to conduct WET tests.

ACTIVITIES IN RESPONSE TO NOTIFICATION OF TOXICITY

Activities in response to a test result that triggers the accelerated testing requirement are

summarized in Figure VI-1. This figure also identifies the person responsible for the action and

the amount of time (in working days) allocated for the action. These actions are described in

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more detail below. City Laboratory Services will notify the other members of the project team,

especially the Environmental Monitoring Section (EMS), as soon as possible after receiving

notification of a WET test failure, but no later than 24 hours. If the WET test failure occurred in

the the C. dubia test, then it is a permit violation and the City must notify EPA within 24 hours of

notification from the lab. The following activities will proceed concurrently, upon receipt of

notification of WET test exhibiting significant toxicity:

The 91st Avenue wastewater operations (WWO) staff, EMS, and LSS staff will

coordinate sample collection for the accelerated testing phase. Sample collection for the

first test of the accelerated testing program should preferably begin within one (1) week,

but no more than two (2) weeks, after LSS provides notification of the test exhibiting

toxicity. Sampling should be repeated every other week thereafter. Samples will be

shipped to BioAquatic and AECOM if the Senior Review Team determines that splitting

the sample is advisable.

If the WET test failure occurs at Outfall 005, the City is required (EPA letter to Randy

Gottler dated October 11, 2011) to reinitiate WET test monitoring at FRW-1 and other

internal FRW locations. The additional data may be helpful in determining the source of

the WET test failures at Outfall 005.

An investigation will be initiated by EMS to obtain information relating to any occurrence

within the wastewater collection system that could have contributed to a WET test

exhibiting toxicity.

The 91st Avenue WWO staff will compile plant operation logs for the period beginning

one (1) week prior to the collection of the samples that exhibited the toxicity trigger, as

well as any additional information on conditions at the plant that could be related to the

test result.

APAI will compile and summarize information provided by the City and forward it to members of

the senior review team or their delegates. Members of the senior review team are shown in

Table VI-1.


Table VI-1 City of Phoenix

Toxicity Reduction Evaluation Workplan

91st Avenue Wastewater Treatment Plant Senior Review Team

Name Affiliation

Randy Gottler City of Phoenix

Bob Hollander APAI

Peggy Glass APAI

Chris Pasch APAI

Rami Naddy AECOM

The senior review team may meet in person or by telephone, and discuss whether the

accelerated testing can be discontinued in accordance with permit provisions. The ESD Deputy

Water Services Director will make the final decision regarding continuation. If accelerated

testing is continued and any toxicity is exhibited during accelerated testing, procedures

described later in this section will be implemented.

ACTIVITIES IN RESPONSE TO WET TEST EXHIBITING TOXICITY DURING

ACCELERATED TESTING

The permit requires that a TRE workplan be submitted within fourteen (14) calendar days of a

WET test exhibiting toxicity during accelerated testing. Concurrent with the development of the

detailed TRE workplan, TIE procedures may be applied to the samples exhibiting toxicity. The

extent of any TIE activities will be discussed by the Senior Review Team.

Development of Detailed Workplan

The City will compile data and information of all unusual occurrences at the plant or in the

collection system. APAI will prepare a summary. At minimum, the summary will present the

results of all toxicity tests and supporting quality assurance (QA) data, beginning with the test

that triggered the accelerated testing requirement. This summary will be transmitted to the

senior review team within five (5) working days of the date APAI receives notification of a test

exhibiting toxicity during accelerated testing.


Within five (5) days after receiving the summary, the senior review team will meet to review the

information and discuss whether to formally recommend initiation of a TRE. The ESD Deputy

Water Services Director will make the final decision regarding whether a TRE will be initiated.

The senior review team will also discuss appropriate modifications to this workplan and a

schedule for implementation of the TRE.

Subsequent to the decision to initiate the TRE, APAI will revise this workplan, as appropriate.

The draft, revised workplan will be distributed to the senior review team for review and

comments. APAI will coordinate with the senior review team to ensure that the workplan will be

submitted within 14 days after receipt of the toxicity test report triggering the TRE.

Environmental Monitoring Services staff will submit the final revised TRE workplan to the EPA.

Initiation of TIE Studies

When a sample exhibits toxicity during accelerated testing, AECOM will conduct a follow-up

screening test of the three daily samples. The purpose of the screening test is to determine

which of the three samples exhibits the strongest toxic response. For the screening test, five

replicates of 100% effluent will be tested for each of the three composite samples. The same

composite sample will be used for the daily renewal (static renewal) of the test chambers.

In some cases, the toxicity may dissipate rapidly, and the toxicant will no longer be present in

sufficient quantities to produce a toxic response during the screening test. If this occurs, no

characterization studies will be performed on this sample. For subsequent sampling and

analyses, a modified screening procedure will be established appropriate for the characteristics

of the toxicant.

TIE studies will be conducted on the sample exhibiting the strongest toxic response. Typically,

a sample will be manipulated as far as possible through the characterization, identification, and

confirmation processes before work begins on a second sample. The investigation of

subsequent samples may be modified based on the results of earlier characterizations.

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SECTION VII

TOXICITY IDENTIFICATION AND REDUCTION EVALUATIONS

The workplan presented herein is in general accord with that described in the Toxicity Reduction

Evaluation Protocol for Municipal Wastewater Treatment Plants, EPA/833/B-99/002 (August

1999). For convenience, the singular is used below (“toxicant,” “compound,” “stream,” etc.),

although it is recognized that more than one toxicant may be detected and may need to be

reduced in order that the objectives of the TRE can be met.

OBJECTIVES

The specific objectives of this TRE are as follows:

Evaluate the pattern and degree of effluent WET test failures;

Identify, to the extent necessary to eliminate WET test failures, the constituent responsible for the observed failures;

Determine, as appropriate, the source of the substance causing WET test failures;

Evaluate and select toxicity reduction programs and/or technologies that result in the elimination of WET test failures so that compliance with the permit is maintained;

Develop an implementation strategy for controlling effluent toxicity.

APPROACH

The steps in achieving the TRE objectives are shown in Figure VII-1. The first step in the

process is to finalize this workplan. The TRE process shown in Figure VII-1 is based on the

following EPA documents:

Methods for Aquatic Toxicity Identification Evaluations, Phase I Toxicity Characterization Procedures, Second Edition, EPA/600/6-91/003;

Methods for Aquatic Toxicity Identification Evaluations, Phase II Toxicity Identification Procedures, EPA/600/R-92/080;


Methods for Aquatic Toxicity Identification Evaluations, Phase III Toxicity Confirmation Procedures, EPA/600/R-92/081;

Toxicity Identification Evaluation: Characterization of Chronically Toxic Effluent, Phase I, EPA/600/6-91/005.

As revised versions of these documents are released, applicable recommendations will be

incorporated into the TRE effort.

While the TRE is in progress, the WWO staff of the 91st Ave WWTP will continue to collect

samples for routine WET testing. Decisions on when and how to take samples for the TRE and

adjustments to the sampling schedule or protocols will be determined by the senior review team.

The liaison between the senior review team and the Wastewater Compliance staff will be the

ESD Deputy Water Services Director or his delegate. Documentation of all sample collection,

test procedures, and test results will be provided to APAI.

Toxicity Identification Evaluation

The TIE studies may include toxicant characterization, toxicant identification, and toxicant

confirmation. These studies will be conducted by AECOM. Chemical analyses will be

conducted by LSS, or by a contract laboratory selected by AECOM with the concurrence of the

City.

The following is a description of each component of a TIE. It should be recognized that all of

the following components will, when practical, be applied to the same sample; i.e., the objective

is to carry the same sample through characterization, identification, and confirmation. After a

toxicant has been identified, the characterization procedure will be repeated to confirm the

results.

Phase I Toxicant Characterization

The objectives of toxicant characterization are to identify the physical/chemical nature of the

toxicant and to provide information on the number and variability of toxic components. Each

manipulation removes, alters, or renders biologically unavailable, a class of chemicals. The

treated aliquots are tested for toxicity, and the level of toxicity in each is compared to the toxicity

of the untreated sample. Examples of the Phase I process follow.


If solid-phase extraction (SPE) removes toxicity, then non-polar organic toxicants may be

suspected. Alternatively, if adjustment to pH 11 followed by filtration removes toxicity, a

material that is relatively insoluble at high pH (e.g., copper or zinc) may be suspected. Table

VII-1 provides a summary of Phase I manipulations and the class of toxicants each addresses.

Several examples of each class are provided.

Several anionic metals and total dissolved solids (TDS) are not removed by any Phase I

manipulation. If there is no removal of toxicity by any of the Phase I manipulations, these

toxicants are implicated.

If the sample is acutely toxic, the acute Phase I methodology will be performed. An acute

Phase I toxicity characterization, typically involves a total of 17 tests. Figure VII-2 depicts the 17

tests, and Table VII-1 provides a summary of typical results.

If the effluent is chronically toxic, a chronic Phase I characterization (Tier I) is conducted.

Although following the same approach as acute Phase I testing, the more resource-intensive

nature of chronic Phase I testing generally dictates that characterization testing be conducted in

two tiers. Tier I tests are a subset of the acute Phase I tests.

Tier I tests generally provide sufficient information to design and implement Phase II

identification studies. Nonetheless, if necessary, Tier II Phase I studies involving pH adjustment

can be conducted.

The characterization may be repeated on several samples. A toxicant should not be targeted

for control actions until at least three tests confirm it is responsible for WET tests exhibiting

toxicity. Toxicant characterization studies will be performed by AECOM.


TABLE VII-1

EXAMPLES OF TOXICANTS REMOVED BY TOXICANT CHARACTERIZATION TESTS

Characterization Test

Toxicant Class Addressed

Toxicant Examples

None (a comparison for other tests)

---

pH Adjustment

Toxicants that degrade under acidic or basic conditions

basic = malathion

Aeration

Toxicants that are oxidizable, volatile, or sublatable

Surfactants or organic compounds

Filtration

Filterable toxicants

cationic metals under basic conditions

SPE (solid-phase extraction with C18)

Non-polar organic toxicants

Pesticides or volatile organic compounds

EDTA Chelation

Some cationic metals

Copper, zinc, or nickel

Oxidant Reduction

Oxidants, some cationic metals

Chlorine, peroxide, copper, or cadmium

Graduated pH pH-sensitive toxicants Ammonia or one of many metals


Phase II Toxicant Identification

The objective of toxicant identification is to identify the specific toxicant or effluent characteristic

that is responsible for WET tests exhibiting toxicity. Phase I results provide an understanding of

the characteristics of the toxicant that is used to select the appropriate Phase II steps. The

description of Phase II approaches for several commonly identified toxicants (or groups of

toxicants) are provided in the following paragraphs.

Non-polar Organic Compounds Non-polar organic compounds are a group of toxicants commonly encountered in municipal effluents. One of the difficulties encountered with non-polar organic compounds is that most effluents contain large numbers of organic compounds; given this fact, direct analysis of the effluent is almost useless for initially identifying candidate toxicants. To resolve this problem, techniques have been developed to isolate and concentrate causative toxicants prior to chemical analysis.

The primary indication of non-polar organic toxicity is complete removal of toxicity by SPE. In these cases, the first step in identification is to elute the causative toxicant from the SPE column using a series of eight different methanol concentrations. Toxicity tests are used to show which methanol fraction(s) contain the causative toxicant. In some cases, high performance liquid chromatography (HPLC) and gas chromatography/mass spectroscopy (GC-MS) techniques can extend these initial results to allow identification of the specific causative toxicant.

Using these techniques, the toxic fractions from the initial separation are concentrated and further separated into 25 fractions using HPLC. Toxic HPLC fractions are then concentrated and submitted for chemical analysis. Procedures for non-polar organic identification are probably the most intensive of those used for commonly encountered toxicants.

Ammonia The presence of ammonia can confuse the results of other tests if TIE studies are not carefully designed. In general, chemical characterization of effluent samples prior to testing provides an indication that effluent may contain toxicity due to ammonia. AECOM has encountered ammonia toxicity in a large number of effluents; with the exception of toxicity attributable to TDS, ammonia is AECOM's most commonly identified effluent toxicant.

For cases where ammonia is suspected to cause chronic toxicity, tests are conducted to determine whether ammonia is, in fact, the only causative toxicant. Procedures used include ammonia spiking, zeolite treatment, graduated pH tests, and testing under a carbon dioxide-enriched atmosphere.

Heavy Metals AECOM has developed a technique to sub-categorize metal toxicity and speed identification of the causative toxicant using the EDTA and oxidant reduction tests. An advantage of this technique is that it directly addresses the bioavailability of the metal, not just its chemical presence.


Several Phase I tests may show responses if heavy metals are present; the exact responses depend on the metals involved. EDTA and/or thiosulfate addition will reduce the toxicity of most cationic metals. Removal of toxicity by filtration at pH 11 is also common, as many metals are not soluble under basic conditions. Though not designed to remove metals, the SPE tests may reduce toxicity somewhat, due to non-specific binding to the SPE column. In most cases, however, metal toxicity breaks through the SPE column fairly rapidly. Manipulations at pH 3 sometimes increase metal toxicity, presumably due to solubilization or mobilization of previously non-toxic metal forms.

Identification studies for metals are commonly less resource-intensive than identification studies for other toxicants. Direct chemical analyses are frequently sufficient.

Total Dissolved Solids The failure to eliminate a toxic response in any of the Phase I characterization tests is consistent with toxicity due to TDS. In many cases, TDS toxicity can be approximated using sodium chloride, but research conducted by AECOM has clearly shown that the toxicity of saline waters is dependent on the specific ionic composition. AECOM has developed salinity/toxicity relationships (STRs). The STRs are a series of logistic regression equations that predict the toxicity of any combination of major ions to three test species: C. dubia, Daphnia magna, and fathead minnows. Splitting samples between two laboratories and a mock effluent containing major ions at the same concentration as in the actual effluent sample can be used to help confirm TDS toxicity.

Surfactants, Flocculants, and Related Chemicals Removal of the toxic response by aeration, filtration, and SPE is typical for these compounds. Analytical methods for surfactants are difficult, and generic screening methods are not available. However, innovative methods are available to assist in identifying surfactants. WET test exhibiting toxicity associated with surfactants in effluents can result from the incomplete treatment of detergent or from water treatment chemicals used within the facility.

Chlorine Chlorine is perhaps the most easily identified of all toxicants common to effluents. A WET test exhibiting toxicity caused by residual chlorine is characterized by the presence of measurable residual chlorine in the sample, the removal of the toxic response with sodium thiosulfate addition, and the rapid degradation of the toxicant during sample storage.

Toxicant identification studies will be performed jointly by AECOM and LSS. AECOM will

manipulate the samples (extraction, ion exchange, etc.) to prepare them for chemical analyses.

LSS or an AECOM contract laboratory will perform the chemical analyses.

The laboratory analyses will be performed in accordance with accepted quality assurance

protocols. Appropriately sensitive analytical methods will be used, and if possible EPA

approved methods will be used. In some cases, it may not be possible to quantify or identify a

pollutant with approved methods. If this is necessary, the laboratory should report the method

and equipment used to conduct the analyses. Most analyses can be performed by LSS. Others

will be shipped to a contract laboratory licensed by the State of Arizona.


Phase III Toxicant Confirmation

The objective of the Phase III confirmation is to confirm toxicants characterized and identified as

the causes of the WET tests exhibiting toxicity. The methods employed will depend on the

results of the characterization and identification studies. Confirmation techniques include

investigation of correlations between the concentration of the suspected toxicant and the degree

of toxicity exhibited by the sample, review of organism response, sample spiking, and

calculation of mass balances. These studies are expected to be performed jointly by AECOM

and the City.

Toxicant Source Identification

If appropriate, toxicant source identification will be performed. Performing the source

investigation concurrently with the toxicant identification study enhances the likelihood of

success for both. The types of activities that may be undertaken as part of this study may

include the following:

Review of available records and information to identify industrial or commercial

establishments that are potential sources of the class of compounds identified in the

toxicity characterization study.

Samples collected from major interceptors will be tested to identify the area contributing

the toxicant. This may require bench-scale treatment of the samples, simulating the

treatment process at the 91st Ave WWTP. Bench scale treatment is necessary to treat

and remove an otherwise toxic substance present in the wastewater. After samples have

been treated in the bench scale process, they can be tested using WET testing. Chemical

analyses of the collection system samples may not require prior treatment.

A bench-scale study, if necessary, will be a joint effort of the City, APAI, and AECOM. APAI will

assist the City in setting up the bench-scale treatment units. The ESD and/or WWO staff will

operate the bench-scale units as determined best by the senior review team, and the LSS. The

LSS contract lab or AECOM will test the treated samples for toxicity. Toxic samples will be

shipped to AECOM for toxicity characterization.


Toxicity Control Evaluation

This part of the study evaluates measures to mitigate the impact of the discharge and prevent

the recurrence of toxicity. Evaluation factors include effectiveness, reliability, feasibility, and

cost. Control methods may be based on source control, treatment at the 91st Avenue WWTP, or

both. The most appropriate approach will be selected based on the toxicant and the source of

the toxicant. Depending on the toxicant, additional studies may be required to determine the

concentration limit that must be maintained to avoid WET tests exhibiting toxicity. An

implementation strategy will also be developed.

TERMINATION OF TRE

The TRE will be terminated based on either of the following occurrences:

An implementation plan for the elimination of WET tests exhibiting toxicity is completed

and approved by EPA.

No WET tests exhibit toxicity during a six-month period and the frequency of toxicity

testing is at least once every month during this period.

Following termination of the TRE, the effectiveness of the implementation plan will be confirmed

by the monitoring performed in conformance with the requirements in the 91st Avenue WWTP

permit.

EPA COORDINATION

It is desirable to have formal and informal contacts and meetings with EPA during the TRE/TIE

to discuss both regulatory and technical issues. It is suggested that a minimum of two formal

meetings be held with EPA. One meeting may occur at the conclusion of the TIE studies when

the nature of the toxicant is determined. The purpose of the meeting would be for the City to

present the findings of the studies and obtain concurrence from EPA on its conclusions and

proposed additional steps. Another meeting may be convened after a toxicant and its source

have been identified. The meeting would be intended to demonstrate the completion of the

TRE/TIE effort and discuss potential permit ramifications.


REPORTS

During the TRE, quarterly progress reports will be submitted to EPA, ADEQ, and GRIC. The

results of all TRE activities and activities planned during the subsequent quarter will be

presented. A final TRE report will summarize the complete project, including:

Results of all toxicity tests conducted during the TRE

Results of toxicant characterization, toxicant identification and toxicant source Identification studies

Results of toxicant confirmation and toxicity control alternatives studies

Conclusions and findings

APAI will prepare this report with support and input from the City and AECOM. APAI will

distribute a draft of each report to project participants for review. Review comments will be

incorporated as appropriate. APAI will provide the City copies of the reports for submittal to

EPA and ADEQ and will distribute copies to the senior review team.

SCHEDULE

The consistency and concentration at which the toxicant is present, the type of toxicant, and the

source of the toxicant all influence the rate at which the TRE can be accomplished. The goal of

the TRE will be to complete the study within the time frame specified in the permit.

APPENDIX A-1

91st Avenue WWTP Flow Schematic

Effluent Management

HeadworksPrimary

Sedimentation Basins

Aeration BasinsInfluentSRO, SAI, 99th Avenue

Secondary Sedimentation

BasinsDisinfection

PVNGS

Tres Rios FRW, OBW

Unified

Liquid Stream Process(Plants 1, 2, 3 UP01 (2008) and UP05(2010)

99 AvenueInterceptors

Prim

ary S

ludge

(P

S)PS Thickening Centrifuge

WAS Thickening Centrifuge

Was

te Ac

tivate

d Sl

udge

(WAS

)

Salt River

BIC

Unified Plant Pump Station

Thick

ened

PS

Recy

cled C

entra

te

Thick

ened

W

AS

ed S

ludge

Thickening Centrate

WAS Thickening Centrifuge

Methane Phase

Acid Phase

Centrate Treatment

Dige

ste(D

S)

Thickening Centrate

Dewatering Centrate

Sludge Cake (Dewatered Sludge)

DS Thickening Centrifuge

Solid Stream Process

91st AVENUE WWTP PROCESS FLOW DIAGRAM AFTER UP05

APPENDIX A-2

Tres Rios Flow Schematic

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