Follow

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- February 2, 2015

Detailed Comments

Comments are divided into the following sections and presented in out line format for ease of

review :

1. Duration Between Sampling Events

2. Normal Plant Operations

3. Representative D4 Release Rate

4. Fish Sampling

– Technical Issues

5. Site

- Specific Sampling Plans

– Direct Discharge Sites

6. Site

- Specific Sampling Plans

- Non

- Industrial and Indirect Discharge Sites

7. Pre

- Mobilization Infor mation Collection Logs

8. QAPP Project Staff Reporting Requ irements and Additional QC Related Issues

9. Method Validation Study

– Vial Headspace

10. QAPP Appendix C

- 2

– Technical Issues

11. Mixing Zone Modeling

12. Overview of EPA’s QAPP Review and Approval Process

1 Duration Between Sampling Events ( Study Plan Section 3.2, Study Plan Sections 7.3 through 21.3 and QAPP Section 2.6.2.2. ). There is no site

- specific information on the sampling schedule included in the Study Plan or QAPP.

ECA Requirement: The ECA (Appendices 1

- 3) specifies that samples shall be taken during two testing events at least three months apart and that the exact dur ation between sampling events for each site shall be determined in a detailed Sampling Plan included in the Study Plan and QAPP

.

The Study Plan provides optimal time frames for monitoring based on low river flow (low dilution) and safety concerns. The provided optimal time periods consist of a two month period (June and July) and a four month period (August through November). Monitoring within these ranges allows for possible durations less than three months as required by the ECA. For example, sampling in July and again in August would result in two testing events only one month apart.

1.1 Please revise the Study Plan and QAPP to include a n overall sampling schedule which lists the proposed dates for each sampling event for each site and sampling location. All task dependencies should be identified and captured in the schedule (e.g., sampling team 1 requires X

- days pre

- /post

- mobilization and cannot sample two sites simultaneously, and other dependencies such as sampling equipment, sampling platforms, holida y schedules, and laboratory capacity).

1.2 EPA recommends that the Study Plan and QAPP be revised to include a discussion of contingency plans in place (e.g.

, alternative sampling schedules that could be implemented if initial sampling condition s are not met )

. EPA suggests that contingency planning include developing alternative sampling schedules based on the assumption that plant operations, weather, or river conditions will preclude sampling as initially planned. EPA also suggests

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the inclusion of measures to be taken to minimize the potential for not achieving the required duration between sampling events (e.g., additional sampling teams, alternative laboratories), as well as the measures that will be taken if the sampling window will not be

met

.

2 Normal Plant Operations ( Study Plan Section 3.2, Study Plan Sections 7.2.3 through 21.2.3, QAPP Secti on 2.6.2.2 and QAPP Section 3.9)

. There is no site

- specific documentation regarding the criteria or means that are used by the facilities to determine normal oper ating conditions in the Sampling Plans.

ECA Requirement: The ECA (Appendices 1

- 3) specifies that samples shall be collected during normal plant operations and during such times that effluent flow rates from the

wastewater treatment system are representative of normal plant operations. The ECA (Appendices 4

- 8) also specifies that normal operating conditions will be established by consulting with the operator of each WWTP, indirect and direct discharge facility. Further, the ECA specifies that th e criteria or means that are used by the facilities to determine normal operating conditions will be documented in the site

- specific Sampling Plans and that confirmation will be obtained that the subject facility is operating under normal conditions prior to commencing sampling at a given location.

2.1 EPA recommends that the normal plant operations discussion be revised to include the following list of plant operations that are not normal:

• Exceeding WWTP design capacity (i.e., hydraulic, organic, and solids loading capacities, as applicable);

• Upsets, as defined by their discharge permits;

• Bypasses, as defined by their discharge permits;

• Utilizing emergency systems, as defined by their discharge permits;

• Noncompliance with any permit requirements or conditions ; and

• Exceedance of any permit limits.

Each of these conditions should be defined for each plant, including discussion of how the conditions will be determined and how they will be documented during pre

mobilization. For example, WWTP operators will provi de plant design capacities, while discharge requirements, conditions, and limitations can be identified from the NPDES permit. These conditions and their pre

- determined status or threshold should be captured

on site

- specific data collection forms. These fo rms would be pre

- populated with each plant’s design capacities and permit limits; yes/no checkboxes would be provided to record upset, bypass, and emergency conditions, as well as compliance with other permit conditions. ERM would complete the site

- specifi c forms during the pre

- mobilization call, including recording actual plant loadings and effluent quality on the form at the time of the call. In the case of conditions that require extended periods of time to assess (e.g., 5

- day BOD testing), and in consid eration of the hydraulic holding time of the treatment system and weather

- induced variation, ERM should record conditions for several days prior to and including the day of the sampling event.

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2.2 EPA recommends the following process for collecting and analyz ing plant operations data:

1 Section 3.2 of the Study Plan (revised to incorporate EPA review recommendations ) lists conditions under which D4 process operations and WWTPs may not be operating under normal operating conditions. This listing will provide a s tarting point for developing site

- specific operation conditions and for defining normal operations. Each plant would start by developing a matrix listing all the parameters listed in

Section 3.2.

2 Each site would then determine whether or not each of the li sted parameters is applicable/relevant to their site; they can also add new, site

- specific conditions to the list as appropriate.

3 For each applicable parameter, the site would then determine whether the parameter can be assessed quantitatively or only qual itatively. For parameters that can be assessed quantitatively, the site would determine whether normal operations for that parameter are best represented by a threshold (e.g., permit limits, design capacity) or a range of normal operation (e.g., MLSS or SR T). Finally, for parameters with a range of normal operation, the site would perform a statistical analysis of historic monitoring data, calculating, for example, mean and standard deviation. For parameters lacking normal distribution, the site can propose an alternative statistical representation of the data.

4 Each site would then develop site

- specific data collection forms. These forms would

include the site

- specific listing of applicable parameters. For parameters measured qualitatively, the form would in clude yes/no checkboxes for ERM to report the plant’s pre

- mobilization operating condition as either normal or not normal, as determined by the plant operator. For parameters that can be measured quantitatively, the form would display the pre

- determined su mmary statistics and also provide space for ERM to collect and record the plant’s current operating conditions.

5 The bottom of the data collection form would include space to provide a narrative discussion of any qualitative parameters recorded as “not norm al,” and any quantitative parameters measured beyond their threshold or more outside of a pre

determined statistical range. The narrative discussions should describe the operating condition of concern, provide the rationale for determining whether or not o peration is normal, and describe the anticipated impact on effluent quality. The rationale for determining normal versus not normal operation will be developed in consultation with the WWTP operator (as required by the ECA), and in compliance with

conditio ns identified as NOT considered normal operations discussed above. If the cause of the operating condition of concern is unknown, or the impact unclear, monitoring should be postponed.

2.3 Additionally, the discussion of normal plant operations should extend beyond WWTP operations, focusing on activated sludge treatment. Revise this section to also address operating conditions at direct discharge sites, including D4 process operations and the types of wastewater treatment systems operated by these plants (i.e. , chemical/physical treatment). This includes, for direct discharge sites, defining plant operations that are not normal, and listing items that indicate that plants may not be operating under normal operating conditions.

3Follow

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- February 2, 2015 April 2, 2015

3 Representative D4 Release Rate ( Study Plan Sections 7.3 through 21.3). There is no site

specific discussion on how the typical rate of release of D4 will be determined.

ECA Requirement: The ECA (Appendices 1

- 3) specifies that samples shall be collected at

a time when the rate of D4 rele ase is expected to be representative of the typical rate of

release of D4 for that site. To meet this requirement, EPA recommends the selection criteria

that follow.

3.1 Please revise the Study Plan (Sections 7.3 through 10.3) to demonstrate that the proposed sample collection schedule for direct discharge sites will meet the following criteria:

1 Confirmation that the processes that generate D4 process wastewater are curr ently operating and generating wastewater that is being fed to the WWTP; and

2 Confirmation that these processes have been operating and generating wastewater as typical during the period of time prior to pre

- mobilization equal to or greater than the hydraul ic residence time of the WWTP.

3.2 Please revise the Study Plan (Sections 11.3 through 20.3) to demonstrate that the proposed sample collection schedule for the non

- industrial and indirect discharge wastewater treatment sites will meet the following criteria:

1 The potential sources of D4 (residential use and/or industrial use), and

2 The days and times these wastewater sources are expected to be received at the POTW (e.g., diurnal cycle and days/hours of industrial operations). For example, if D4 is expected in consumer personal care products (such as deodorants and shampoos), D4 release rates from consumers might be expected in the morning when most people shower (and accounting for hydraulic residence time of the collection system).

4 Fish Sampling

- Technical Issues

4.1 The QAPP and Study Plan state that the techniques and recommendations for fish collection described in the ECA (i.e., USEPA 2003a (Section 7.0 Procedures, pp. 3

- 5) and Powell and Woodburn (2009, Sample Collection, p. 8)) were generally followed. However, several other fish collection techniques (gillnets, trap/hoop/Fyke nets, and angling) that were not described in the ECA are also described for possible use based on site

- specific conditions. These other commonly used fish collection procedures we re based on EPA guidance (Fish Field Sampling, Operating Procedure SESDPROC

- 512

- R3, EPA Region 4, April 2011).

ECA Requirement: The ECA (Appendix 8) states:

The exact method for collection of fish is a site

- specific determination. During preparation of t he site

- specific Sampling Plans, the physical nature (e.g., width, depth, flow) of the receiving water will be determined and used to guide the selection of the appropriate method of sample collection. For each site, collection procedures will be

4Follow

- up to the March 9, 2015 letter from EPA: Additional Comments on the Study Plan and QAPP for Octamethylcyclotetrasiloxane (D4)

- February 2, 2015 April 2, 2015

based, as appropriate to the characterization of the receiving water, on USEPA 2003a (Section 7.0 Procedures, pp. 3

- 5) and Powell and Woodburn (2009, Sample Collection, p. 8). This guidance identifies two main types of fish collection methods for relatively

shallow and slow moving water and gives direction on choice of method, general practices, and other considerations for the field work. For each site, the exact collection method for fish samples will be detailed in the site

- sp ecific Sampling Plans and QAPP.

EPA recommends that the SOP be revised to include a description of the parameters and conditions under which each type of fish collection method would be preferred at each site. In addition, it is recommended that documentation be provided by the field cre w describing the fish collection method used and the supporting rationale. This clarification

should be made throughout the QAPP and Study Plan.

4.2 Sample Collection Procedures

– Fish

. The approach in the Study Plan and QAPP is inconsistent with the ECA requ irements to focus first on collecting different trophic levels before collecting based on abundance (e.g., the study plans state throughout that the two most abundant species collected will be selected for analysis, and if practicable, they will

represent two different trophic guilds). This needs to be modified throughout the QAPP and Study P lan

.

ECA requirement: The ECA (Appendix 8) states:

On the day of field sampling at a given site, fish shall be collected and sorted by species. The taxonomic identification of each fish species shall be noted. Two species of fish from different trophic guilds, if practicable, collected in sufficient mass s uch that individual or composite samples can be prepared for the analysis of D4, shall be selected. If adequate quantities of fish from different trophic guilds are not available the two most abundant species will be selected. Information about the life hi story of the two species selected shall be included in study reports. The individual fish will be measured for length and weight.

The QAPP must also address the QA/QC of the taxonomic determinations of the fish made in the field. The QAPP should prescribe procedures for the review to ensure the collected fish are accurately identified and classified. This review step should preferably be performed in the field such that fish collection can be reattempted immediately if needed. If this review step is not pe rformed until the laboratory, reattempt of fish collection may be

difficult.

4.3 Sample Collection Procedures

– Benthic Organisms (QAPP Section 3.2.1.5). The QAPP states, “in the event that 100 grams of benthic organisms cannot be obtained, the

absolute minimum mass of benthic organisms required is 25 grams.

ECA Requirement: The ECA (Appendix 8, Figure 5) specifies that a total mass off 100 grams of benthic organisms should be collected.

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- February 2, 2015 April 2, 2015

EPA emphasizes, as discussed previously, that if grab does not yield sufficient sample mass, then the effort should be repeated in an adjacent location. Please revise the Study Plan and QAPP as appropriate.

5 Site

- Specific Sampling Plans

- Direct Discharge Sites

Comments 5 .1.1 and 5 .1.2 within this section are ECA requ irement s that must be addressed. The remaining c omments within this section ( Comments 5 .1.3 through 5 .1.6 ) are considered

technical deficiencies that should be addressed , unless previously identified as an ECA requirement (e.g. comments pertaining to “normal plan t operations” must be addressed).

5.1.1 Study Plan Sections 7.2.3 through 10.2.3. Please revise to describe how each of the criteria and conditions listed in Study Plan Section 3.2 will be evaluated specific to each site. Additionally, please develo p site

- specific call log forms for insertion into Study Plan Sections 7.2.3 throughn10.2.3, listing each of these criteria and conditions and their pre

determined range or threshold for acceptable sampling (i.e., normal plant operations,

duration between s ampling events, typical and unusual weather conditions, period since unusual weather, and representativeness of typical rates of release of D4).

5.1.2 Study Plan Sections 7.3 through 10.3

. Please revise to incorporate how an assessment of normal operating conditions will be considered in determining sampling timing and

schedule.

5.1.3 Study Plan Sections 7.5 through 10.5 and Figures 7

- 1 through 10

- 1. Please revise “Sampling Locations Description ” sections and “Site Location: figures to include greater

detail.

5.1.4 Study Plan Figures 7

- 2 through 10

- 2. Please revise “Wastewater Treatment Plant Process Flow Diagram” figures to clearly indicate sampling and flow measurement

locations.

5.1.5 Study Plan Sectio n 9.2.2 and Figure 9

- 2. The “Wastewater Treatment Plant Process Flow Diagram” figure appears to show primary clarifiers following neutralization and before equalization; however, this treatment step is not included in the “WWTP Process Description” section . Please correct this oversight.

5.1.6 Study Plan Section 10.2.2 and Figure 10

- 2. The “Wastewater Treatment Plant Process Flow Diagram” figure remains largely illegible, but appears to show primary clarification between the oil/water separator and the air strip per; however, this treatment step is not included in the “WWTP Process Description” section. Additionally, the chemical precipitation and flocculation

- sedimentation treatment steps included in the “WWTP Process Description” section do not appear to be incl uded in the indicated “Wastewater Treatment Plant Process Flow Diagram” figure. Please correct this oversight.

6Follow

- up to the March 9, 2015 letter from EPA: Additional Comments on the Study Plan and QAPP for Octamethylcyclotetrasiloxane (D4)

- February 2, 2015 April 2, 2015

6 Site

- Specific Sampling Plans

- Non

- Industrial and Indirect Discharge Sites

6.1.1 Study Plan Sections 11.5 through 21.5, Figures 11

- 1 through 21

- 1 and Figures 11

- 2 through 21

- 2

. The “Sampling Locations Description” sections and “Site Location” figures lack sufficient detail. Please revise text and figures as appropriate. Additionally, please revise the “Process Flow Diagram” figure for each site to c learly indicate sampling

and flow measurement locations.

6.1.2 Study Plan Sections 11.3 through 21.3. Please revise the “Sampling Timing and Schedule” section to incorporate how assessment of “Normal Operating Conditions” will be considered in determining sampl ing timing and schedule.

6.1.3 Study Plan Sections 11.2.3 through 21.2.3. Several of the selected WWTPs are served by combined sewage systems with permitted combined sewer overflows (CSOs). For these WWTPs, please revise “Normal Operating Conditions” sections t o describe the combined sewage systems, the CSOs, and the historical frequency, extent, and conditions of CSO discharges (e.g., intensity and duration of precipitation events). Describe the fate and transport of discharges from known and likely D4 industri al users under CSO discharge conditions. Describe the criteria that will be used to determine whether and under what conditions periods of CSO discharges will be considered normal operating conditions. Furthermore, for indirect discharge WWTPs (Study Plan Sections 17.2.3 through 21.2.3), describe the criteria that will be used to determine that the WWTP influent shall reasonably be expected to contain D4. Describe how these conditions and determinations will be documented during pre

- mobilization. If samplin g is conducted conditions of CSO discharges, describe how these conditions (extent and nature) will be documented in the field notes and final report.

6.1.4 Study Plan Sections 11.2.3 through 21.2.3. Certain of the selected WWTPs have treatment system bypasses used during emergency conditions. Please revise the “Normal Operating Conditions” section to indicate that use of these bypasses is not considered normal operating conditions. Additionally, please describe how these conditions will be documented during pre

- mobilization.

6.1.5 Study Plan Tables 12

- 2, 15

- 2, 16

- 2, and 18

- 2. Please confirm whether historical monitoring data provided is for BOD5 or CBOD5 and revise tables as appropriate.

6.1.6 Study Plan Section 11.2.2. Please revise the “WWTP Process Description” sect ion to describe the Emergency/Polishing Pond and its historical frequency, extent, and

conditions of use. Describe the criteria that will be used to determine whether and under what conditions use of the pond will be considered normal operating conditions. If sampling is conducted during use of the pond, describe how these conditions (extent and nature) will be documented in the field notes and final report, and how flows to and/or from the pond will be accounted for when reporting the influent and effluent flow rates.

6.1.7 Study Plan Figure 11

- 2

. Please provide a replacement “Process Flow Diagram” as tank

volumes and other small text are not discernible.

7Follow

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6.1.8 Study Plan Section 12.2.2

. Please revise the “WWTP Process Description” section to provide additional infor mation regarding the planned addition of an external carbon dosing facility (e.g., chemical/source name, construction dates, date dosage is scheduled to commence).

6.1.9 Study Plan Section 12.0, Appendix I

. Boulder’s discharge permit indicates that flow

measure ment occurs only at the wastewater influent. Please describe how effluent flow

will be measured or estimated.

6.1.10 Study Plan Section 13.2.3. Please revise the “Normal Operating Conditions” section to provide additional information regarding the planned biosol ids loading facility and co

generation engines (e.g., construction and implementation dates) and the anticipated

“short

- duration interruptions” (e.g., interruption of the entire WWTP only sludge management) and their impacts on sampling.

6.1.11 Study Plan Sectio n 13.5. Please revise the “Sampling Locations Description” section to clarify whether the effluent sampling location is before or after chlorination/dechlorination. Additionally, please discuss the representativeness of the selected biosolids sampling loca tion, as Study Plan Section 13.5 indicates samples will be collected as the biosolids exit the belt filter presses, while Study Plan Section 13.2.2 and Figure 13

- 2, “Process Flow Diagram” describe that digested sludge is dewatered via centrifuges or belt f ilter presses.

6.1.12 Study Plan Section 14.0, Appendix I

. Please revise Appendix I to include this WWTP’s discharge permit.

6.1.13 Study Plan Section 14.2.3

. Please revise the “Normal Operating Conditions” section to provide additional information, regarding the planned centrifuge dewater system and polymer change (e.g., installation/construction and implementation dates, does the polymer contain D4).

6.1.14 Study Plan Section 16.2.2 and Figure 16

- 2. Sludge thickening using dissolved air

floatation is discussed within t he “WWTP Process Description” section but is not included in the “Process Flow Diagram” figure. Additionally, flocculation is not discussed in the “WWTP Process Description” section but is present on the “Process Flow Diagram” figure. Please revise the tex t and figure as appropriate.

6.1.15 Study Plan Section 17.2.2. Please revise the “WWTP Process Description” section to describe the “high strength” wastewater sources and their management, including the use and objectives of the “BAR” treatment unit indicated on Figure 17

- 2. Additionally, please revise text to discuss sludge thickening using the rotary drum thickener.

6.1.16 Study Plan Section 17.2.2. The narrative is inconsistent regarding the use of polymers. Text within the “WWTP Process Description” section states “Polymers are not used at the WWTP.... No information is available on the presence of siloxanes in the polymers

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used at the WWTP.” Also, Study Plan Section 17.5 mentions “the polymer tank room.” Please address this oversight.

6.1.17 Study Plan Section 17.5. The d escription of the biosolids sampling location is unclear. Please clarify what is meant by the “post belt processing machine.”

6.1.18 Study Plan section 18.1 and Table 18

- 2. There is a discrepancy in the reported 2013 average flow (65.7 MGD v.s. 71.96). Please co rrect this oversight.

6.1.19 Study Plan Section 18.5. Please revise the “Sampling Locations Description” section to better describe the effluent and biosolids sampling locations.

6.1.20 Study Plan Section 19.1 and Appendix I. The “Site Description” section describes a design average flow rate of 32 and 40 MGD for dry and wet conditions, respectively. However, the discharge permit specifies a design average flow rate of 54 MGD. Please revise the text as appropriate.

6.1.21 Study Plan Section 19.9.2 and Figure 19

- 2. The text states “sludge that settles in the intermediate...clarifiers is returned to the tricking filters...”; however, the process flow diagram shows that sludge from the intermediate clarifiers is returned to the bar screens. Please correct this oversight and revise text and figure as appropriate.

6.1.22 Study Plan Section 21.0, Appendix I

. Please revise Appendix I to include this WWTP’s discharge permit.

6.1.23 Study Plan Section 21.2.2, Study Plan Section 21.5 and Figure 21

- 2. The “Process Flow Diagram” figure depicts and the “ WWTP Process Description” section describes that digested sludge is dewatered via centrifuges or lagoons, while text within the “Sampling Locations Description” section specifies that samples will be collected as the biosolids exit the post

- digestion centr ifuges. Please revise text and figure to discuss the representativeness of the selected biosolids sampling location

.

7 Pre

- Mobilization Information Collection Logs (Study Plan Appendix G)

7.1 EPA recommends that s ite

- specific call logs for the direct, indirect and non

- industrial sites be developed based upon comments above for Study Plan Sections 7 through 21. The site

specific call logs for indirect and non

- industrial discharge sites will record both influent

and effluent flows, while the logs for the direct discharge sites will only record effluent

flows. Appendix G of the Study Plan provides an example call log form.

7.2 Study Plan Appendix G (Pre

- Mobilization Information Collection Logs) for Direct Discharger WWTP #DD1, Adrian, MI. The call log form for this direct discharger should record flows for both Outfall 001A (process wastewater discharge compliance point) and Outfall 001B (treated ground water); daily flow measurements at these outfalls are required by the plant’s NPDES per mit. The plant’s call log form should also indicate whether “High

- Strength Wastewater” is being routed to the WWTP at the time of sampling

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and during the period of time prior to pre

- mobilization equal to or greater than the hydraulic residence time of the WWTP.

7.3 Study Plan Appendix G (Pre

- Mobilization Information Collection Logs) for Direct Discharger WWTP #DD2, Carrollton, KY. The call log form for this direct discharger should record flows at the time of sampling for both Outfall 001 (compliance point) an d Outfall 002 (internal compliance point); continuous flow measurements at these outfalls are required by the plant’s NPDES permit.

8 QAPP Project Staff Reporting Requirements and Additional Quality Control Related

Issues

8.1.1 QAPP Section 2.4. Descriptions of the how communications and any reporting relationships between the ERM QA Unit and the ALS QA Managers will be handled are needed in the QAPP. The signoff or approval trail of project QA and management personnel indicating that the data generated are appropriate for use needs to be

documented. For example, it is stated in the body of the QAPP that the ERM Data QA Manager will communicate with the ALS quality staff, but that communication is not

reflected in Figure 1

- 1. Further, the independence of the ALS QA Unit Managers with those ALS staff working directly on the project analyses needs to be documented.

8.1.2 QAPP Section 2.8.2. The QAPP states that the validation study will be repeated at ALS/SLC in early 2015. Please provide validation results for ALS Salt Lake City.

8.1.3 QAPP Section 2.9.3 and Appendix D. It is stated that a description of the EQUIS EDD format will be provided in Appendix D. This Appe ndix only contains a listing of several data elements. There is no description of the format of all data elements that will be submitted to EPA. Please provide this information.

8.1.4 QAPP Section 3.5 and Appendix F

. Corrective Actions for sample QC failure are not defined in the QAPP, analytical SOPs in Appendix F, Section 14 of all analytical SOPs,

and Section 13 for SOP OE

- DC

- LIPIDS. The SOPs mention that if QC fails, Nonconformity and Corrective Action Reports (NCAR) are req uired and routine corrective actions are part of normal operating procedures and no other documentation (other than laboratory or maintenance logs) are necessary. If there are known routine corrective actions that are part of the operating procedures, they are not mentioned in the SOPs, which is where this type of information should be located. For example, if a CCV percent recovery fails, it is common practice that samples that are bracket ed within a passing CCV and a failing CCV are re

- analyzed. If CCVs c ontinue to fail, the instrument can undergo a cleaning or maintenance cycle or the CCV solution can be re

- prepared.

Please revise the SOPs to include guidance as to what is routinely done when a QC fails and if there are different steps for different failed QC samples. This is to ensure that the laboratory will re

- analyze samples if QC fails or if they flag samples and what they commonly do in such occasions. Additionally, please include corrective action

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procedures for all types of QC in case of failure, such as IS, CCVs, Blanks, field spikes and surrogates, hold times, and anything that has acceptance criteria

.

9 Method Validation Study

– Vial Headspace (QAPP Section 3.4.3 and Appendix C). The QAPP states that D4 analytical SOPs were prepared for the water matrices, solid matrices and tissue samples. EPA expects clarification of the issues surrounding headspace in sample vials that were expressed in the March 9, 2015 letter. Specifically, it is expected that SEHSC will revise the Study Plan and QAPP to include an explanation (and relevant documentation) of how the analytical techniques will account for the headspace

.

ECA Requirement: The ECA (Appendix 4) specifies that the commercial laboratory will develop a method for analyzing D4 that shall be adapted from the analytical method specified in Knoerr (2013). The ECA further specifies:

The Knoerr (2013) analytical m ethod utilizes pieces of LDPE film to act as a sorbent and partial barrier to prevent loss of analyte to the headspace of the sample container. Immediately after collection, a water sample is placed into a container containing pieces of LDPE, which adsorbs the D4. In the laboratory, the water sample and the LDPE sorbent are solvent extracted and pro cessed for analysis with GC

- MS.

10 QAPP Appendix C

- 2

– Technical Issues

10.1 The method validation reports fail to provide the date and time of analysis following sample preparation. Were the samples analyzed immediately after preparation, or did the study authors use a holding time that would mimic the actual holding times that would be experienced when field samples are taken?

10.2 Suggest adding to all validation rep orts in Appendix C2 a su mmary of quality control sample results and passing criteria, such as Internal Standard (IS) added to samples not just in calibration curve, field spike (if it was added), pre/post

- extraction spiked surrogates, and

blanks.

10.3 Validati on Reports are vague on how each calibration point was obtained. The validation reports should p rovide the weight of standard ( the actual not just target weight)

.

10.4 Provide an example of the sequence including calibration, QC samples

, and blanks in the

orde r these are analyzed in SOPs or Reports.

10.5 Define what is a long sequence and when multiple Procedural Blanks (PBs) between samples are required.

• Provide number of PBs analyzed and analysis position in the sequence.

• Suggest analyzing PBs at the end of each sequence

.

10.6 Provide volume of extracted sample poured into autosampler vial. A large sample was prepared and 50 mL were used for each sample, but how much of each sample was poured into the autosampler vials?

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10.7 Provide date and time, and volume of solution and vial for the following:

• Prepared bulk sample

• Individual 50 mL samples ( only v olume was provided)

• A utosampler vials ready for analysis

10.8 Recommend that a set of samples is analyzed the same day of preparation and another set should be analyzed after a pe riod of time that equals the amount of days that real samples will be from collection to analysis.

10.9 Provide date and time of sample analysis

.

10.10 Provide calibration standards and QC samples preparation date and expiration date

.

10.11 Provide total run time.

11 Mixi ng Zone Modeling (Study Plan Section 2.5.6 and Appendix F) Comments in this

section are based upon the following ECA requirements :

1. Samples are to be collected from the receiving water environment (i.e., surface water, sediment, and benthic) at a location as near to the outfall as is possible after “adequate” mixing of the discharge plume and ambient flow has occurred.

2. M onitoring shall not occur within three days of an unusual weather event, such as heavy rain storm. Thus, receiving water flows used in the modeling effort should be consistent with typical dry weather flows for the time of year in which monitoring will occur.

11.1 Summary Comments

11.1.1 The Study Plan fails to provide justification for applying the 100

- meter downstream sampling location to the direct discharge, non

- industrial and indirect discharge wastewater treatment plant sites.

11.1.2 EPA recommend s that “adequate mixing” be evaluated on the basis of complete vertical mixing unless modeling produces unreliable or unfeasible results. Tracer studies shoul d be considered for sites if modeling is inapplicable.

ECA Requirement: The ECA (Appendix 8) specifies:

At each site, benthic organisms shall be collected as close as reasonably possible to the effluent outfall provided adequate mixing of the discharge and receiving water has occurred and where adequate benthic organism sample masses are obtained. Each site specific sampling plan will identify where the effluent and receiving stream are adequately mixed and the basis for the determination. At each site fish, surface water

and sediment shall also be collected at a pproximately the same location.

11.1.3 The Study Plan does not provide adequate details on the modeling inputs and the rationale for the chosen values for the direct discharge sites.

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11.1.4 While the choice of 100 m for the direct discharge sites appears more appropriate than the other two approaches proposed by the Study Plan (constant dilution factor and complete mixing), this distance may result in more dilution than is necessary and may be

inconsistent wi th the goals of the ECA.

11.1.5 Monitoring at multiple distances downstream could compensate to some degree for the uncertainty of determining when mixing has reached the benthic layer.

11.2 Dilution Summary and Recommendation

11.2.1 As stated above in Summary Comment 9.1.2, EPA recommends that “adequate mixing” be evaluated on the basis of complete vertical mixing unless modeling produces unreliable or unfeasible results (i.e., sampling location on the order of kilometers downstream). In instances where modeling is ina ppropriate, due to channel geometry or other confounding factors, mixing should be evaluated using field studies and best professional judgment.

11.2.2 EPA cannot make recommendation s regarding the non

- industrial and indirect discharge wastewater treatment plant (WWTP) sites based on information presented in Study Plan

Section 2.5.6.2

, as no modeling was performed or data reported for these sites

.

EPA recommend s that either modeling and/or field studies be completed for the non

industria l and indirect discharge WWTP sites . Dilution modeling is site

- specific. Mixing

zone s imulations performed for the direct discharge (DD) sites are not applicable to the

non

- industrial and indirect discha rge WWTP sites described in the Study Plan, unless there is a high degree of correspondence between the dischar ges and receiving water

bodies.

11.3 General Comments

11.3.1 As stated above in Comment 9.1.2 and Comment 9.2.1, “a dequate mixing” should include vertical mixing consideration. To fully characterize and evaluate the resulting

expos ure of aquatic and sediment dwelling organisms, the sampling location should ensure sediment dwelling organisms are exposed to the effluent plume. For the intent of the ECA Testing Program, EPA recommend s that “adequate mixing” be defined at or beyond the point of complete ve rtical mixing unless i t violates another part of the Study

P lan . Other considerations may be applicable, and should be discussed within the Site

Specific Sampling Plan s

.

11.3.2 Benthic organisms’ exposure to the discharge will be limited until the spreading line of the plume reaches a riverbed. Exposure will be maximized once complete vertical mixing

has occurred. For three of the four direct discharge facilities ( #DD1

- Adrian, #D D2

- Carrollton, and #DD4

- Waterford), the Study Plan assume s an equal effluent density to receiving water density and discharges occur at the surface of the receiving water

, which is likely to indicate these effluent will mix in the vertical at a slow rate. For #DD3

-

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Friendly, the effluent is buoyant and discharged from a submerged single point outfall located just above the bottom of the stream which will tend to produce rapid vertical mixing rates.

11.3.3 The Study Plan defines dilution factor as the ratio of ambi ent receiving water to effluent flow in the plume at the location of interest ( Study Plan Section 2.5.1.2, page 32). The Cormix User Manual uses a slightly different definition of dilution

, which differs from the Study Plan definition by one unit (i.e., St udy Plan Dilution = C ormix Dilution

– 1). The Study Plan does not explicitly state that they have corrected for this differen ce in the Study Plan

.

11.3.4 The Study Plan does not specify whether centerline dilution (i.e., peak concentration at a downstream distance) or flux

- averaged dilution (i.e., average concentration at downstream distance) is being specified. At any given downstream location, the

centerl ine dilution would be more stringent than (i.e., less than) the flux

- averaged dilution. Please refer to Figure 1 1

- 1 for further illustration. Outside of the jet region of the plume, Cormix calculates flux

- averaged dilution so this is likely to be the value presented in the Study Plan since the distances being discussed are hundreds to thousands

of meters downstream.

Figure 11

- 1. Centerline versus Flux

- Averaged Dilution

11.4 Study Plan Section 2.5.6

The Study Plan asserts that it is necessary to identify the mixing zone for each WWTP and direct discharge effluent discharge to be sampled, and that the availability of well

- defined mixing zones, such as those established in an NPDES permit, was determined during site

visits.

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Typical mixing zones established in NP DES permits are not optimal for purposes of characterizing average, long

- term exposure in the receiving water environment. Regulatory mixing zones in permits are typically based on reasonable worst

- case conditions applicable

to acute and/or chronic conditi ons with reoccurrence intervals corresponding to water quality standards (for instance, 1

- day out of three year returns). The use of regulatory mixing zones may not be consistent with “normal operations” or typical dry weather receiving water flows specifi ed within the ECA.

11.5 Study Plan Section 2.5.6.1

11.5.1 The Study Plan asserts that the inputs to the model were based on best estimates of realistic conditions of the river at each facility and various flow rates. Limited rationale is provided for the modeling in puts, and we were unable to substantiate the use of many of the individual model inputs (for further discussion on inputs, please refer to Section 9.6). This conclusion is based upon a review of Study Plan Section 2.5.6, Study Plan Section 7.0, Study Plan Section 10.0 and Appendix F.

11.5.2 The Study Plan states that model output was evaluated to develop a consistent approach to determine the zone of “adequate” mixing for all DD site s. The Study Plan explores three approaches:

1. Complete mixing

– Complete mixing is def ined by the Study Plan in Appendix F as “where the plume is uniform both vertically and horizontally throu ghout the

river cross

- section.” Modeling estimates show complete mixing did not occur within 100 km downstream under any of t he modeled river flow rates for the

#DD2

- Carrollton facility, nor for the highest modeled river flow rate for the

#DD3

- Friendly facility. The distance to complete mixing for the #DD4

- Wa terford facility exceeded 3 km.

At the distances required for complete mixing, the Study Plan finds that several other contributing sources (both point source discharges and tributary inflow) to the rivers occur between the outfall and the complete mixing distance. These additional contributing sources int roduce confounding effects that cannot be

overcome. The Study Plan concludes that in order to have consist ency between sites and to help e nsure that sampling is not conducted too close to the effluent outfall or too far downstream, the distance to complete mixin g could not be used as the point of adequate mixing.

EPA agree s that the long distances necessary for complete mixing are inappropriate for the purpose and intent of the ECA Testing Program. Additionally, the available dilution factors associated with com plete mixing

exce ed 100:1 ( i.e., the ratio of receiving water to effluent), and are not consistent with “low dilution” as specified within the ECA Testing Program.

2. Constant dilution factor

– The Study Plan proposes the consideration of a constant dilution factor to determine the point of “adequate mixing” . The Study Plan points

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out that the #DD4

- Waterford facility did not achieve a dilution of 10 until just past 150 m from the discharge point at the lowest modeled river flow rate, while

the #DD1

- Adrian facility was predicted to achieve a dilution factor of 10 in just

2. 4 m. The Study Plan asserts that at a distance of 2.4 m the receiving water will be mostly effluent which, since it is in direct contraventio n of the modeled estimate, indicates a lack of faith in the relia bility of the modeling results.

The Study Plan does not provide rationale for why they find a distance of 150 m too far away and leaves the assertion unsubstantiated

. However, EPA agrees wit h

the Study Plan ’s conclusion based on the requirements of the ECA that the monitoring location be as close to the effluent outfall as possible, and that unnecessary dilution be minimized.

Based on the Study Plan ’s modeling results for the #DD1

- Adrian fac ility, at a distance of 2.4 m downstream of the effluent outfall, the receiving water is expected to be mostly receiving water (i.e., a dilution factor of 11:1). Based on the model, the assertion that the receiving water will be mostly effluent is

unsubsta ntiated and unlikely. This was the Study Plan ’s sole rationale for discounting the constant dilution factor approach, and is further referenced as rationale for supporting the third and chosen approach.

Performing monitoring based on a constant dilution f actor, irrespective of the behavior of the effluent plume and the exposure to target organisms

, is not consistent with the intent of the ECA Testing Program. The use of a constant dilution factor may result in monitoring locations where benthic organisms a re not exposed to the effluent plume. Thus, we agree that the use of a consistent dilution factor is inappropriate for determining adequate mixing.

3. Use of a constant distance (100 m)

- The approach eventually accepted by the Study Plan to define “adequate ” mixing was the use of a constant distance of 100 m downstream of the effluent outfall. The chosen approach seems to rely on three

claims:

a. No other discharges to the receiving rivers were identified within 100 m of any of the direct discharge WWTP sites.

b. This distance was neither too close to the facilities effluent (as would be the case if a specific dilution factor were used) or too far away (as would be the case if complete mixing were used).

c. The other two options (complete mixing and constant dilution factor) have been determined to be inadequate.

That there are no other discharges to the receiving rive rs within 100 m of any of the direct discharge WWTP sites is an important consideration but is not sufficient in and of itself to define adequate mixing. The Study Plan does not discuss the appropriateness of the approach in regards to collecting data adequate to address the purpose and intent of the ECA Te sting Program. Specifically,

whether benthic organisms are exposed to the effluent plume within 100 m of the

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effluent outfall and whether the effluent diluted more than reasonably necessary at

100 m.

Adequate mixing must be defined and evaluated consistent with the purposes and intent of the ECA. Identification of a sampling location consistent with purposes and intent of the ECA should result in a sampling location where benthic organisms are exposed to the effluent plume and should not result in significantly more dilution than necessary at that location.

11.6 Study Plan Section 2.5.6.2

11.6.1 The Study Plan states that because of difficulties encountered during modeling of the selected DD facilities, and the lack of correspondence between the predicted and actual location of the plume at a field training site ( #DD2

- Carr ollton facility), th e mixing zone

for t he municipal POTW s were not modeled. Instead, the same 100 m downstream distance is proposed as the potential sampling location for all si tes.

The lack of correspondence between the modeling results and the field observations at

the #DD2

- Car r ollton facili ty may indicate inappropriate input values were used in the modeling effort or that an incorrect Co rmix module was used. The Study Plan should provide further discussion regarding the difficulties encountered and explanation for the lack of correspondence between the modeling results and the field observ ations. At a minimum, the Study Plan should evaluate and document whether effluent and receiving water conditions were representative of model inputs on the date field observations were

made.

Additional discussion should be given to explaining the infeasibility of resolving the identified issues with the modeling effort. For instance, could field testing be used to calibrate the Cormix simulation and, if not, why is this standard technique inap propriate

or infeasible in this instance?

11.6.2 For the non

- industrial and indirect discharge WWTP sites that were not subject to dilution modeling, it is not ideal to assume monitoring at 100 m downstream of the effluent outfall is adequate for the purposes an d intent of the ECA Testing Program. Without additional data to evaluate the effluent plume, there is no supporting evidence to suggest that benthic organisms are exposed to the effluent plume at 100 m at each of the facilities. Mixing processes are site

- s pecific. The downstream distance need to reach complete vertical mixing at one site will have no bearing on another site. With the direct discharge facilities, site

- specific modeling data indicated that vertical mixing had occurred prior to the sampling lo cation, but there is no evidence to support such a findin g for the remaining facilities.

However, due to cost considerations, it may be practical to assume vertical mixing has occurred within a given receiving stream at a downstream distance of 100 m if t he following holds:

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• The receiving water to effluent flow ratio is low whe n compared to the DD facilities;

• Stream depths are consistent with the characteristics of the DD fa cilities receiving streams; and

• The efflu ent is not excessively buoyant.

11.6.3 For the n on

- industrial and indirect discharge WWTP sites that were not modeled, the Study Plan does not provide information regarding the presence or absence of additional point sources or non

- trivial tributary flows into the 100 m downstream mixing intervals.

If a dditional point sources or tributary inflows are identified between the effluent outfall and the receiving water monitoring location, the potential impacts of those point sources

should be evaluated.

EPA conclude s that due to the lack of data and analysis provided within the report for the

non

- industrial and indirect discharge WWTP sites, it is not possible to evaluate consistency with the ECA Testing Program requirements that facilities be selected with low dilution, and that the receiving water location be located as close as possible to the effluent outfall where adequate mixing occurs.

11.7 Appendix F

11.7.1 Model Selection

– The author does not indicate which Cormix module is uti lized for each modeling effort.

11.7.1.1 Cormix1 should be used in instances where the discharge is emitted from a single port diffuser (either submerged or plunging), which has a substantial jet or momentum component into flowing unstratified or stratified receiving water environments.

Facilitie s that appear applicable based on Appendix F summaries: Friendly, WV

Figure 11

- 2 Cormix1

11.7.1.2 Cormix2 should be used with submerged multiport diffusers under the same general characteristics as CORMIX1. This model does not appear to be applicable any of the four facilities described in Appendix F.

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11.7.1.3 Cormix3 should be used when an effluent enters a larger water body laterally, through a canal, channel, or near

- surface pipe without a substantial jet component and is also positively or neutrally buoyant. Faciliti es that appear applicable based on Appendix F summaries: Adrian, MI Site; Carrollton, KY; Waterford, NY.

Figure 11

- 3 Cormix3

11.7.2 Effluent and Receiving Water Flow Inputs

– Selected flow inputs used in the modeling, broadly speaking, should reflect the issue under investigation. For instance, when investigating acute mixing conditions, flow inputs should typically be based on a reasonable, worst

- case scenario (i.e., high effluent flow rates and low/dry

- weather receiving water flow rates). When investigating a verage long

- term exposure (as is the

case under this ECA ), inputs should be based on long

- term averages (i.e., average dry weather effluent flow rate and median/harmonic mean/geometric mean receiving water flow rates). Section 2.5.6.1 of the Study Plan sta tes that inputs to the model were based

on best estimates of realistic conditions of the river at eac h WWTP and various flow

rates. However, it is unclear from Section 2.5.6.1 and the Appendix F memos how effluent and receiving water inputs were selected. For instance, were the effluent flow inputs developed based on an analysis of flow data and, if so, what was the analysis and why are the selected flows appropriate?

For the Carrollton facility

, the receiving water high flow inputs represent the 90 th
percenti le of the daily mean flow rates; this is inconsistent with the Waterford facility

where the 80 th percentile of daily flow rates was used. Low and high flows are undefined for the Adrian and Friendly facilities. T he Study Plan should define the ran ges of acceptable receiving water flows, and provide the rationale for the asserted ranges in regards to the intent of the ECA Testing Program.

Were effluent flow inputs based on design capaciti es or some other assumed value? If inputs are not to be based on averages or typical values, input parameters could also be selected such that they roughly approximate typical seasonal conditions anticipated during the period in which sampling is anticipated to occur. The ECA requires the monitoring occur at least 3 days following unusual weather, thus dry weather receiving water flows would be most app ropriate.

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Appendix F should provide the rationale to support each of the individual modeling inputs for the intended purposes of investigating “normal” operating condit ions and

t ypical dry weather stream flow.

11.7.3 Stream Geometry

– The Cormix models assume fairly regular channel geometries

, which are unrealistic over the distances (i.e., kilometers) discussed in the Study Plan. In winding streams and river, Cormix will produ ce more accurate results within the nearfield (i.e., dozens of meters downstream) than in the farfield (hundreds of meters downstream). In channels with many interruptions (i.e., sandbars) near the discharge location, modeled estimates of mixing are unlike ly to produce reliable estimates of mixing.

11.7.4 Disjunction Between Modeled Plume Location And Field Observed Location

– The modeling efforts will provide reasonable estimates of plume location under circumstances where inputs are similar to conditions on the day of sampling. It is rarely the case that models and reality correspond cleanly. Given the incomplete and limited mixing predicted by the models and the irregularity of some channels described, use of a tracer test to confirm the sampling location is wi thin the influence of the discharge at each site

is recommended.

12 Overview of EPA’s QAPP Review and Approval Process

12.1.1 QAPPs document the what, how, where, why and when of a project in addition to noting the specific QA system that governs the project and the quality control activities that have been put in to place to detect, manage and correct actions that need fixing. QAPPs reflect the current state of the project and are designed to accommodate the need to change procedures during the course of the stud y, if warranted. QAPPs are living documents that are kept current over the conduct of the study.

12.1.2 It is critical that those who will approve the QAPP understand the process that will be followed to make changes to study protocols. In many cases minor chang es can be made during the conduct of the work (with the needed approvals) and then are reported in interim and final reports. Major changes must be documented and approved by those who approved the original (or previous revision) QAPP before the change is implemented. In some cases such changes can be approved via phone or email in real time, following up with the appropriate documentation and signatures.

12.1.3 The implementation of QAPPs follows a c hange process that ensures that users of the QAPP are aware of the changes made in real time, and clearly when a new revision is issued and approved. Revisions in this context generally reflect major changes to study protocols for data collection, analysis, use and reporting. These changes are reported in a

Revision History that accompanies the QAPP. The Revision History documents the change(s) made, the reason for the change and where the change was made in the document (via the page number). This allow users to quickly learn of changes made, to track them, and to ea sily locate the revised text in the document. One approach often used when revised QAPPs are sent to the project team for review and specifically to those who will approve the QAPP is to provide a “Markup” copy of the QAPP, in addition to the

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“Clean” versi on. New signature pages documenting that all signers of the QAPP have reviewed and approved of the changes are also prepared.

12.1.4 The first version of a QAPP is o ften submitted for review sev eral times before it is approved. The first version of an approved Q APP is documented as Revision 0. After each revision is approved, the Revision Number increases by one. For this reason, the QAPP that is currently under review will be considered Revision 0 once it is approved by

EPA.

12.1.5 Further details are needed describin g how EPA will be informed in a timely manner on significant quality control issues that arise during the conduct of the project activities and that require corrective actions that deviate from procedures that are documented in the QAPP.

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