1 

### RESPONSE TO COMMENTS

City of Puyallup

Wastewater Treatment Plant

NPDES Permit WA003716 8 September 23

, 20 1 4

On April 6

, 201 3 , the U.S. Environmental Protection Agency (EPA) issued a public notice

for the reissuance o f the City of Puyallup Wastewater Treatment Plant (W WTP) National Pollutant Discharge Elimination System (NPDES) Permit No. WA 0037168

. This Response

to Comments provides a summary of significant comments and provides corresponding EPA

responses. The comments resulted in the fol lowing changes to the permit :

 A cute Whole Effluent Toxicity ( WET ) testing is eliminat ed and the trigger for accelerated testing and the Toxicity Reduction Evaluation is changed to a TU
c of 1.9. The WET test species and tests are clarified.

 The r eporting date for WET testing is changed “ from with the discharge monitoring reports (DMR) for the month following sample collection ” t o “ with the DMR s for the month following the receipt of the results from the lab oratory

. ”

 The typograp hical error referencing Part II.G. in Condition III.I., Public Notification

is corrected to reference Part II.F.

 The effluent limitation range for pH is increased from a lower value of 6.4 in the draft permit to a lower value of 6.1 in the final permit. The f inal pH range is the same as in the previous permit.

 The arsenic Minimum Level ( ML ) for effluent monitoring in Table 2 of the permit is changed from 10 μg/L to 0.5 μg/L

.

 Condition I.B.7. is revised to allow a method that detect s and quanti fies arsenic

.

 Condition I.D.8. is revised to allow a method that detect s and quanti fies arsenic

.

 The frequency of toxic organics sampling required under the pretreatment monitoring requirements, Part II.A.8.i) is clarified and established as once per year.

 Exceptions to pH violations applicable to continuous monitoring are added

.

 T o allow sufficient time for completion

, the submission of the local limits evaluation

is delayed to December 31, 2015.2

After consultation with the Puyallup Tribe and as require d by the final 401 Certification the following conditions are added to the final permit:

1. Quarterly monitoring of e ndosulfan monitoring is required for five years. This will allow a sufficient number of samples to determine if the discharge has reasonable potential to cause or contribute to a violat ion of the Puyallup water quality standards

for endosulfan

.

2. A study is added to the permit to identify the source of lead and zinc in the effluent and identify opportunities for reduction. Lead and zinc effluen t limitations are eliminated in the reissued permit based on the Puyallup’s authorized mixing zone.

A uthorization of a mixing zone is contingent on this added study.

A second condition of the mixing zone authorization is monitoring at the edge of the mixing zones. This condition is added to the permit.

3. A Mercury Minimization Plan and annual status report is added to the Permit.

4. T he Tribe is authorizing a mixing zone for lead, zinc and mercury as identified in the

table below

. With these mixing zone s , there is no reasonable potential to violate the water quality standards for these pollutants.

Minimum Mixing Zone for No Reasonable
Potential to Violate the Puyallup Water Quality Standards

(Percent of Receiving Water Flow)

lead zinc Mercury

Acute End of Pipe 2.1 End of Pipe

Chronic 3.3 4.0 20

Comments were received from the following:

Robert Andreotti, Director of Public Works, City of Puyallup (City)

1. Comment: With the exception of one Total Recoverable Zinc result in November 2006,

the violations listed below are in error.

1. 31 July 2009

– Total Recoverable Mercury . The value reported was above the threshold of the method detection limit, 0.0001 μg/L, but too low as to be quantifiable. Puyallup has never had an effluent mercury result that exceeds

limitations.

2. 30 Jun 2006

– Nitrogen Ammonia, Total

– The origin of the values listed are unknown. Puyallup’s records indicate that for the month of June 2006 the3 monthly ammonia average was 0.49 mg/L and that the daily maximum value was 1.30 mg/L. Both values are well below permit limitations and consistent with typical concentrations.

3. 30 April 2008

– Lead, Total Recoverable

– The values reported on Puyallup’s DMR for April 2008 list the monthly average value of 0.5 μg/L and a monthly maximum value of 0.5 μg/L. These values are well below the limits of 6.1 μg/L and 10.5 μg/L, respectively.

Response: T he EPA agrees the Fact Sheet Table 1 listing of total re cov erable mercury

and total recov er able lead as violations is an error. The listing of nitrogen ammonia as a

violation coul d not be verified. This comment does not result in any changes to the permit.

2. Commen t ( City ) : The effluent limits in Table 3 of the Fact Sheet for the draft permit

contain the following errors

.

BOD 5 , mg/L, lb/day, percent removal

– A sampling frequency of 5 episodes per week is listed; whereas, Puyallup’s existing permit and draft permit list 3 episodes per week.

TSS , mg/L, lb/day, percent removal

- A sampling frequency of 5 episodes per week is listed; whereas, Puyallup’s existing permit and draft permit list 3 episodes per week.

Fecal Coliform Bacteria, #/100 ml

- A sampling frequency of 5 episodes per week

is list ed; whereas, Puyallup’s existing permit and draft permit list 3 episodes per

week.

pH, std. units

- The Maximum Daily Limit for Puyallup’s existing permit is listed

in the Fact Sheet as 6.4

– 9.0 standard units; whereas, the actual existing permit

limitat ion is 6.1 to 9.0.

Response: The EPA agrees with the comment , the Fact Sheet was incorrect and inconsistent with the draft permit

. The sampling frequency for BOD 5 , TSS, and fecal coliform was correct in the draft and final permit and is 3 episodes per week. The percent

removal for BOD 5 and TSS is calculated from the average values for the month. The

effluent limit for pH in the final permit is revised (see re s ponse to Comment # 15 ).

3. Comment : Fact sheet Table 4

- Receiving Water Monitoring Requirements in the Puyallup River does not contain monitoring requirements for mercury; whereas, annual testing is required in the draft permit. Additionally, copper is listed without indicating speciation; whereas, in the draft permit it is listed as dis solved.

Response: The receiving water monitoring requirements in the permit are correct and are required . Annual mercury receiving water monitoring is required and dissolved copper is the species required to be reported.4



### 4. Comment: Fact Sheet Section E. Outfall Evaluation states 

### :

“ In early 1998 the City modified the existing diffuser to prevent damage by gravel

and rocks. The diffuser ports are now angled downstream with a “Tide Flex” valve

connected with a neoprene sleeve and flange. To ensure that the new diffuser is not damaged by sediment deposition, the draft permit requires the City to conduct an annual outfall evaluation. ”

The draft permit does not contain this requirement.

Response : The fact sheet was inconsistent with the pe rmit. However the permit is the

enfo rceable document, not the fact sheet

. In accordance with the permit, t he City is not required to conduct an outfall evaluation

.

5. Comment: The Fact Sheet requires the City to conduct a comprehensive

infiltration/inflow study identifying the causes of untreated/primary treated overflows and submit a report within three years that contains deadlines for correcting the problems. However, this requirement is not in the draft permit and Puyallup objects to its inclusion

for t he reasons below.

1. The Fact Sheet states that Puyallup is to perform ... evaluation of the sewerage facility and a system

- wide inventory/evaluation survey that identifies the causes of the untreated/primary

- treated overflows .... The word ‘causes’ suggests that P uyallup has had an ongoing problem with untreated/primary

- treated overflows. However, with the exception of one equipment failure that resulted in a limited duration overflow in 2013, the Puyallup treatment plant has had no other overflows in the fifteen y ears since a major upgrade that began in 2008.

2. The design of the Puyallup’s facility does not physically allow for the intentional bypass of primary or partially treated wastewater.

3. The City completed a comprehensive city

- wide infiltration and inflow study in 2012

where 24 individual basins were monitored and the volume of infiltration and inflow

was characterized.

4. Puyallup continues in 2014 to identify and repair major sources of infiltration and inflow with $300,000 allocated in its capital budget to infi ltration/inflow reduction and dry

- weather smoke

- testing pending for later in 2014. An additional $250,000 allocated to system improvements.

Response: The fact sheet is inconsistent with the permit. T he permit, not the fact sheet is

the enforceable document . Since the permit does not contain this requirement

, t he City is not required to conduct a comprehensive infiltration/inflow study.

6. Comment 

### : Puyallup strongly objects to the requirement to sample for arsenic in the Puyallup River

. Although the CWA may authorize EPA to require sampling and reports5

the basis of the requirement does not seem justified by EPA’s or the Department of Ecology’s reckoning

. The Department of Ecology study, Results and Recommendations from Monitoring

Arsenic Levels in 303(d) Listed Rivers in Washington (Ecology publication number 02

- 03

- 045) ( Ecology Report )

, states:

“There is significant uncertainty regarding the accuracy of the current
arsenic criteria for human health. Even EPA is reluctant to impose the criteria (62 FR 42179, August 5, 1997) that they promulgated on Washington
State through the National Toxic Rule.”

Low

- level sampling and analysis is fraught with opportunities for accidental contamination and erroneous results. Puyallup does not possess the expertise to handle or filter samples for dissolved arsenic. The rigorous sampling, handling, and analytic requirements are detailed in the Ecology report as well as in EPA Method 1669. As stated in the Ecology Report, sampling and analyti c costs are high for the different speciations of arsenic. Puyallup does not believe it has the responsibility or capability to re

characterize or augment the arsenic data collected by the Department of Ecology. This is

a task best left to the expertise of a regulatory agency such as EPA or the Department of Ecology.

Response: The EPA believes the City has the capability and responsibility to conduct the sampling for total and inorganic arsenic in the Puyallup River

. Federal regulations at 40 CFR122.44 (v ii) states

“When developing water quality

- based effluent limits under this paragraph the permitting authority shall ensure that:

(A) The level of water quality to be achieved by limits on point sources established under this paragraph is derived from, and complies with all applicable water quality standards;...”

The Puyallup Water Quality Standards contain both total arsenic criteria for protection

of aquatic life and inorganic arsenic criteria for protection of human health. I t is the responsibility of the City of Puyallup to provide the monitoring necessary to e nsure that its discharges comply with the water quality s tandards.

On page 3.2 of EPA’s Permit Writers Manual,, September 2011, Section 3.2 Major Components [of an NPDE S permit], Permit Bullet 3 states:

All NPDES permits consist, at a minimum of...

“ Monitoring and Reporting Requirements: Used to characterize wastestreams and receiving waters (emphasis added)

... ”

The permit includes both inorganic and total recoverable arsen ic monitoring for reasonable potential determination of aquatic life and human health arsenic criteria

. Monitoring for the Ecology Report conducted in 2002 at the Meridian Street Bridge (Monitoring S tation 10A070 ) upstream of the discharge only include d one i norganic6

arsenic sample , the speciation of the criteria for protection of human health

. One sample is inadequate to determine reasonable potential for violations of the human health

standard for arsenic. The ambient water quality data for inorganic arsenic is necessary to assess the reasonable potential for the effluent to exceed the inorganic arsenic criteria. Therefore inorganic receiving water monitoring is retained.

The permit is unchanged.

7. Comment : The Ecology R eport contains other salient facts that argue against the proposed arsenic sampling:

...the comparability of the data is confounded by differences in the year and season of collection, sampling procedures, analytical methods, and detection limits.

Response:

 To address concerns about variation in arsenic concentration by year
, the effluent and receiving water monitoring is required over five years.

 To address concerns about variation in arsenic concentrations over different

seasons
, effluent and receiving water monitoring is required to occur during all

four seasons.

 As the C ity reported on Application F orm 2A Part D

, Supplemental Application

Information

, the analytical method for arsenic is 200.8. This method will allow a

minimum l evel (ML) of 0. 5 μg/L. Table 2 in the permit is revised to include an

ML of 0. 5 μg/L for arsenic.

 The total recoverable, dissolve d and inorganic arsenic monitoring is required by

the Puyallup Tribe’s 401 Certification and must be included in the permit un der Clean Water Act Section 401(d).

Arsenic monitoring is retained in the final permit

.

8. Comment: The Ecology Report stated a rsenic levels in Washington rivers and streams should be attributed to natural sources, unless shown otherwise. The Ecology Report also

stated exceedances of the N ational Toxics Rule arsenic criteria are to be expected in Washington rivers and streams. Additionally, as noted in the Department of Ecology report, background concentrations of arsenic in the Puyallup River already exceed Tribal human health standards by nearly 56 times.

Response: The permit is consistent with the recommendations in the Ecology Report. T he Ecology Report for the Puyallup River shows background concentrations of

total recoverable arsenic exceeding th e human health criteria. However human health

criteria is based on inorganic arsenic T he Ecology Report contained only one sample o f inorganic ar s enic. One sample i s inadequate for a reasonable potential determination for

arsenic discharges to violate the water quality standards for human health . Adding to the7

uncertainty of inorganic arsenic in the receiving water is provided in a conclusion in t he Ecology Report on page 14 qualifying its data by the statement: “These dissolved data may underestimate tota l inorganic arsenic by a substantial amount. ”

The Ecology Report is inconclusive regarding the source of arsenic in the Puyallup

River. If the exceedance is from anthropogenic sources as demonstrated by the monitoring the sampling will aide in an evalua tion of the need for listing of arsenic in the vicinity of the discharge

.

Further, t he Puyallup Tribe is requiring the mon i toring of arsenic in the 401 Certification.

T he Ecology Report on page 16 state s “ i t is not possible to state with certainty what the natural background is for arsenic in Washington rivers and streams. Additional monitoring will help identify natural background. ” The permit provides this additional monitoring.

T he Ecology Report state s “W ater quality data considered for future 303(d) arsenic listings should clearly demonstrate that any exceedances of standards are due to anthropogenic sources, and should include some measurement of total inorganic arsenic ”

. The permit provides the moni toring recommen d ed by the Ecology Report. As the fact

sheet states the permit requires the City to conduct a limited round of inorganic arsenic monitoring to determine whether or not there should be a follow up study to determine if

arsenic in the treatment plant effluent is naturally

- occurring arsenic, or if it is of commercial or industrial origin.

The permit is unchanged.

9. Comment: Puyallup operates an Industrial Pretreatment Program required, approved, and periodically audited by EPA. All co mmercial and industrial users complete a comprehensive survey to determine the nature of their business and the character of pollutants discharged. Users either receive discharge permits from the City or Letters of Authorization (LOA) to discharge. Puyallu p has an arsenic limitation in its sewer use ordinance that was developed using EPA methodology and approved by EPA. Puyallup

has no known commercial or industrial contributors of arsenic. Consequently, arsenic sampling is not justified on the basis of det ermining if arsenic in the treatment plant effluent is naturally

- occurring arsenic, or if it is of commercial or industrial origin.

While it is reasonable to conclude that potable water likely contributes arsenic to the

wastewater effluent it is not contr ibuted at the concentrations given in the Fact Sheet.

Response: T he City’s arsenic limitation in its sewer use ordinance and the arsenic in the potable water supply are not adequate to characterize effluent discharges for arsenic. The influent arsenic monitoring and concentrations in the potable water supply may not be representative of arsenic in the effluent. Arsenic in the potable water supply could explain the source of arsenic in the Puyallup WWTP effluent but it is the effluen t that

must be monitored. Monitoring effluent discharges is required to cha ra cterize the8

discharges. The permit requires monitoring of the effluent for inorganic arsenic since the criteria for protection of human health is inorganic arsenic not total arsen ic.

The Department of Ecology determined in 2002 that arsenic concentrations in Washington rivers and streams are typically in the range of 0.2

- 1.0 ug/L, whereas concentrations greater than 2 to 5 ug/L may indicate contamination from anthropogenic

sour ces.

Further, the potable water supply from the Green River may vary by season as it does in the Puyallup River causing seasonal variations in arsenic discharged from the WWTP.

Seasonal m onitoring during the four seasons will characterize any variations that may occur. The seasonal arsenic monitoring remains as a permit condition.

As the fact sheet stated the ambient and effluent monitoring will aide in determining if the arsenic is naturally occu r ring or from commercial or industri a l origin.

10. Comment: As part of its Pretreatment Program the City has been conducting bi

- annual testing and reporting of its influent and effluent for total arsenic concentrations for 10 years resulting in approximately 140 tests of influent and effluent over this ti me period. Because of the rigorous sampling requirements for low

- level analysis, and the time required to specially clean and prepare equipment for ‘clean’ sampling per EPA Method 1669, Puyallup requests that the proposed quarterly sampling be removed from the draft permit and replaced with adding inorganic arsenic to the list of pollutants to be tested in Part II.A.8., pg. 18 for pretreatment . By doing this six separate samples of both influent and effluent will be taken twice annually for five years on t hree consecutive weekdays rather than the four annual samples proposed in the draft permit.

Response: See Response to Comment 7 Bullet 2 concerning seasonal sampling. The 140 samples was required by the pretreatment requirements of the permit. That sampling requires one sample between January 1 and June 30 and one sample between July 1 and December 30. This monitoring frequency is not equivalent to quarterly seasonal sa mpling

. Bi

- annual sampling does not provide the seasonal sampling frequency required to characterize the discharges for arsenic. Arsenic varies by season as stated in the Ecology Report. “ During low flow, mainstem concentrations were 0.76 to 1.0 ug/L.

Conc entrations were lower d uring high flow

– from 0.21 to 0.52 ug/L”

As the fact sheet states the monitoring of the inorganic, dissolved and total arsenic coinciding with quarterly ambient will help evaluate partitioning.

To the extent that pretreatment effluent monitoring required in Part II.A.8. satisfies the requirement for quarterly arsenic monitoring, these samples may be used to satisfy the requirements of Part II.B. Arsenic Monitoring. See Response to Comment 1 1

.

Th e permit is unchanged.

11. Comment : The methods used for sampling and analysis are typically dictated by the concentration of the analyte or the required sensitivity of the analytical procedure. In the case of drinking water, the Safe Drinking Water Act (SDW A) allows as much as 10 μg/L9

(ppb); whereas, the human health criteria given the consumption of both water and aquatic organisms together is 0.018 μg/L (ppb)

– a level 555 times lower than the

SDWA.

The Ecology Report stated the NTR [National Toxic Rule] arsenic criteria are at or below the detection limits of routinely available analytical methods

The water quality concentration of 0.018 μg/L (ppb) requires special clean sampling procedures as prescribed by EPA Method 1669 (EPA 1995). Puyallup’s water sampling is conducted at a level of care required for a limit of 10 μg/L (ppb) and does not use the se techniques. Therefore, analytical ‘blips’ are probable. Of 27 potable water sampling events conducted 2002 through 2011, only 4 were at the level cited in the Fact Sheet.

Additionally, Puyallup’s effluent arsenic data, graphed in the Fact Sheet (pg. 16) shows a maximum concentration below 1.4 μg/L (ppb). Based on 69 influent clean sampling episodes conducted since 2003, Puyallup has never reported an influent value exceeding 2.8 μg/L.

Response:

. See Response to Comment 6.

The EPA disagrees that sam pling and analytical sensitivity must be at the level of the human health standards. The sensitivity must be at a level to detec t arsenic concentrations

or at the ML

.

Effluent Monitoring

For all effluent arsenic monitoring Puyallup must use sufficiently sensitive analytical methods which meet the following:

(i) Use a method that detects and quantifies the level of arsenic, or

(ii) Use a method that can achieve a maximum ML less than or equal to those specified in Table 2 Maximum MLs for Pollutants Not Subject t o Effluent

Limitations

Table 2 requires an arsenic ML of 10 μg/L for effluent monitoring. The EPA is requiring the most sensitive ML from an EPA approved analytical test method. The most sensitive ML is 0.5 μg/L from the approved analytical method s 200.8, Inductively Coupled

Plasma

- Mass Spectrometry (ICP

- MS) and 200.9, Graphite Furnace Atomic Absorption, for effluent monitoring of total and dissolved arsenic. The ML in Table 2 is changed from 10 μg/L to 0.5 μg/L.

The graph on page 16 of the fact sheet sh ows a minimum arsenic total recoverable concentration of 0.6 μg/L. The Comprehensive Non

- Conventional Pollutants Effluent Sampling , City of Puyallup WPCP submitted with the application reported arsenic levels

between 0.6 μg/L and 1.3 μg/L

, and t otal r ecoverable arsenic monitoring by Ecology at the Meridian Street Bridge from 2012 and 2013 ranged from 0.51 μg/L to 1.12 μg/L

. Based on these samples a method with a ML of 0.5 μg/L will detect the minimum

concentration of total recoverable arsenic

.10

The lev els of inorganic arsenic concentrations, the speci ation of the human health criteria,

are unknown and must be characterized. The ML remains at 0.036 ug/L

.

Th e requirement to either detect and quantif y the concentration or achieve the ML applies to all pa rameters without effluent limitations. Therefore the following Condition replaces

Condition I.B.7. that restricted monitoring to methods that can achieve MLs for parameters without limits.

Final Condition I.B.7.

“For all effluent monitoring, the permittee must use sufficiently sensitive analytical methods which meet the following:

Parameters with an effluent limit. The method must achieve a minimum level (ML) less than the effluent limitation unless otherwise specified in Table 1 Effluent Limita tions and Monitoring Requirements.

Parameters that do not have effluent limitations.

(i) The permittee must use a method that detects and quantifies the level of the pollutant, or

(ii) The permittee must use a method that can achieve a maximum ML less than or equal to those specified in Table 2 Maximum MLs for Pollutants Not Subject to Effluent Limitations;

For parameters that do not have an effluent limit, the permittee may request different MLs. The request must be in writing and must be approved by EPA.

See also Part III.D Monitoring Procedures ”

Ambient Monitoring

The M D L for ambient total recoverable and dissolved arsenic are 0.5 mg/L. This M D L is

above the human health standard. The sensitivity must be at a level to detect arsenic

concentrations or at the M D L.

The draft permit required samples that achieve method detection limits (MDL) that are less than or equal to those in Table 3. To further address the comment on detection limits at the human health standard Condition I.D.8. is changed to allow the arsenic sampling method to achieve either detection and quantification or the MDLs.

“With the exception of arsenic samples must achieve method detection limits (MDLs) that are equivalent to or less than those listed in Table 3. The permittee may request different MDLs. The request must be in writing and must be approved by EPA.11

For ars enic the permittee must use sufficiently sensitive analytical methods which detects and quantifies the level of arsenic or a method that can achieve a maximum MDL less than or equal to those specified in Table 3.”

In various sections of the Ecology Repo rt and the Fact Sheet b ased on limited data arsenic was reported above the human health standard.

 Total recoverable concentrations range from approximately 0.76 ug/L to over 1.5 ug/L during low flows as shown on pages 16 and 17 of the fact sheet

.

 The E cology Report reported a mbient arsenic during high flows in the rang e of 0.21 ug/L to 0.52 ug/L

 The Ecology Report reported for the Puyallup River a mean total receiving water

arsenic level of 0.71 μg/L and a minimum of 0.47 μg/L well above the human

heal th standard (data from August 2001

- Au gust 2006) and for the most part above the 0.5 μg/L M L.

 The Ecology Report reported ambient arsenic during low flows between 0.76 and 1.0 ug/L.

This limited data indicates arsenic in the Puyallup River is above th e human health

standard. However, this data is limited and insufficient to determine reasonable potential to violate the water quality standards for arsenic.

Except during periods of high flow a method with a M L of 0.5 ug/L is capable of measuring these c oncentrations.

The inorganic arsenic concentration in the Puyallup River was found to be 0.40 mg/L based on one sample. This concentration is also higher then the human health criteria but with only one sample insufficient to determine a reasonable potential for human health

.

12. Comment: The draft permit requires total, dissolved, and inorganic arsenic monitoring quarterly for five years. In their study, the Department of Ecology typically collected samples from the Meridian Street Bridge in Puyallup or by wading into the river or with a sample bottle on the end of a polyethylene pole. Samples were primarily taken in spring and fall not during the wet season. All soils contain arsenic. Puyallup does not believe that an unbiased sample can be collected from the river bank and be guaranteed to be free of contamination from the bank itself. And, the only time the river can be safely waded is

in mid

- fall.

Response : The data provided in the Ecology Report for spring is cited as the “high flow’

season sampled using polyethylene poles from shor e or by wading and was representative of arsenic in the Puyallup River

. The City can sample using this method to obtain representative samples.12

T he permit require s the City to w ork with the Puyallup Tribe to establish monitoring stations in the Puyallup River. T he upstream monitoring station is required to be at a minimum distance of 100 feet from the facility’s outfall. Although it would be feasible to

use the Meridian Street Bridge as it is more than 100 feet upstream from the facility’s

outfall the City must work with the Puyallup Tribe to establish the monitoring station

. Further, this monitoring is required by the Tribe’s 401 Certification and must be included in the permit under Clean Water Act Section 401(d).

13. Comment: In conclusion, it is u nclear how EPA plans on using any collected data. The requirements have the potential to subject Puyallup to spurious and costly arsenic limitations based on caprice and not based on any realistic expectation that limitations will result in any measurable improvement toward meeting human health criteria

.

Response: As the fact sheet states the permit requires the Permittee to conduct a limited round of inorganic arsenic monitoring to determine whether or not there should be a follow up study to determine if arsenic in the treatment plant effluent is naturally

occurring arsenic, or if it is of commercial or industrial origin.

14. Comment: In Fact Sheet Part X. Other L egal R equirements discussing temperature monitoring as a reasonable and prudent measure the fourt h paragraph states that continuous monitoring of effluent and river upstream monitoring is required. The draft permit requires both upstream and downstream monitoring.

Response: The fact sheet contains a n error by not including the requirement for

downstr eam monitoring. The fact sheet is not enforceable but is an explanation of the requirements in the permit. Although the fact sheet does not address downstream monitoring the permit does contain the requirement to monitor downstream. Therefore the City is r equired to conduct downstream monitoring.

15. Comment: Appendix C

– Basis for Effluent Limitations, Table C

- 8 Determination of pH
Limits erroneously uses the acute dilution factor of 1.9 rather than the chronic dilution factor of 13.6. The point of compliance with pH is the boundary of the chronic dilution zone. The corrected lower pH limit remains unchanged from 6.1 s.u. in the existing permit and is not 6.4 s.u. as indicated in the draft permit.

Response: The EPA agrees. The Table below shows at a discharge with a pH of 6.1 s.u. the City is within the water quality standard of 6.5. The effluent limitation for pH is changed from 6.4 in the draft permit to a final limit of 6.1 . This is the same pH effluent

limit in the previous permit.13

16. Comment: The infor mation on changes to the ammonia level is incomplete. Two of the items we checked appeared to be incorrect:

Appendix D states that 50 ammonia data points were used for ammonia calculations. Appendix E contains over 100 dates with ammonia data between Augu st 2003 and

December 2011. Which dates were used and what is the basis for their selection?

The coefficient of variation (CV) was calculated based on only 50 ammonia data points. The CV based on the complete set of data is significantly less than the 1.75 value used according to the fact sheet. Puyallup requests that EPA share the spreadsheet files used to

make the calculations for ammonia Reasonable Potential and Limits.14

Response: Reas on able poten tial and effluent limitations for ammonia were developed seasonally. As the fact sheet states t he data used are DMR results from August 2003 through December 2011, there are 50 data points for this period during the months of November through April. The calculated CV is 1.754. Appendix D Table D

- 2 shows 50

data points used for ammonia for the periods November through April and 52 data points for the periods May through October. The total is 102 data points.

Seasonal Period from May through

October NH3 mg/L Seasonal Period

from November through April NH3 mg/L

8/31/2003 3.9

9/30/2003 2.3

10/31/2003 2.2

11/30/2003 2.6

12/31/2003 1.1

1/31/2004 2.7

2/29/2004 9.3

3/31/2004 1

4/30/2004 0.6

5/31/2004 0.7

6/30/2004 0.4

7/31/2004 1.3

8/31/2004 2.5

9/30/2004 0.8

10/31/2004 0.4

11/30/2004 0.5

12/31/2004 0.4

1/31/2005 0.8

2/28/2005 0.5

3/31/2005 0.6

4/30/2005 0.6

5/31/2005 0.4

6/30/2005 0.7

7/31/2005 1.6

8/31/2005 0.5

9/30/2005 2.1

10/31/2005 0.5

11/30/2005 0.3

12/31/2005 0.2

1/31/2006 1.8

2/28/2006 0.315 3/31/2006 0.3

4/30/2006 0.3

5/31/2006 0.5

6/30/2006 6

7/31/2006 2

8/31/2006 0.9

9/30/2006 2.3

10/31/2006 0.2

11/30/2006 1.2

12/31/2006 0.8

1/31/2007 3.9

2/28/2007 0.3

3/31/2007 1.1

4/30/2007 0.9

5/31/2007 0.1

6/30/2007 0.1

7/31/2007 1.4

8/31/2007 1.1

9/30/2007 0.9

10/31/2007 1.6

11/30/2007 0.2

12/31/2007 0.6

1/31/2008 0.2

2/29/2008 0

3/31/2008 0.1

4/30/2008 0.1

5/31/2008 0.1

6/30/2008 0.2

7/31/2008 1.5

8/31/2008 1.3

9/30/2008 0.8

10/31/2008 0.2

11/30/2008 0.2

12/31/2008 0.4

1/31/2009 4.3

2/28/2009 1.7

3/31/2009 0.2

4/30/2009 0.1

5/31/2009 0.1

6/30/2009 0.1

7/31/2009 0.316 8/31/2009 1.8

9/30/2009 2.9

10/13/2009 2.9

10/31/2009 1

11/30/2009 0.3

12/31/2009 0.1

1/31/2010 0.3

2/28/2010 0.1

3/31/2010 0.1

4/30/2010 0.1

5/31/2010 0.2

6/30/2010 0.1

7/31/2010 0.7

8/31/2010 1.8

9/30/2010 0.2

10/31/2010 0.4

11/30/2010 0.3

12/31/2010 0.4

1/31/2011 0.2

2/28/2011 0.1

3/31/2011 0.1

4/30/2011 0.2

5/31/2011 2.2

6/30/2011 7.3

7/31/2011 0.3

8/31/2011 0.2

9/30/2011 0.4

10/31/2011 0.6

11/30/2011 0.3

12/31/2011 0.7

Count 52 50

Mean 1.25 0.87

Standard deviation 1.422163 1.522384

CV 1.137731 1.749867

17. Comment: Ammonia limit calculations should be based on Puyallup River pH and temperature data pairs , not individual pH and temperature values. It is erroneous to

assume that the 95 th percentile value for pH would occur on the same day as the 95 th
percentile for temperature. There is now a substantial amount of river pH and temperature17

data that can be used for data pair selection so “limited data” is not a valid argument for rejecting this method.

Response: When selecting a reasonable worst

- case value for temperature and pH, the

EPA and states use the percentile value derived from a cumulative frequency distribution analysis of a complete data set of pH data and a complet e set of temperature

. This provides more conservative protection for water quality and is more practical than attempting to p ai r pH and temperature.

The Technical Support Document for Toxics Control (EPA, 1996) recognize s the use of paired data when extensive data are available. The City is asking for a change from the steady state modeling using worse case condit i ons for pH and temperature with “ single, constant inputs for effluent flow, effluent concentration, backgroun d receiving water

concentration (RWC) [i.e. ammonia] , receiving water flow, and meteorological conditions (e.g., temperature) ” (Section 4.5.1 Wasteload Allocation Methods, page 78). The alternative, dy namic modeling

, includes more than simply finding pairs . It requires more

data “ us ing estimates of effluent variability and the variability of receiving water assimilation factors to develop effluent requirements in terms of concentration and variability. The outputs from dynamic models can be used to base pe rmit limits on probability estimates of receiving water concentrations rather than worst

- case conditions.” “ In general, dynamic models account for the daily variations of [i.e. temperature and pH] and relationships between flow, effluent, and environmental

conditions and therefore directly determine the actual probability that a water quality

standards exceedance will occur. ” “ Dynamic modeling determines an LTA that will be adequately protective of the WLA, which relies on actual flow data ther eby reducing the need to rely on worst case critical flow condition assumptions. ”

For example the continuous s imulation models have the advantage compared to steady

state formulation of “cross

- correlation and interaction of time

- varying pH, flow temperature, pollutant discharges, and other parameters are incorporated.” However they require significantly more data for input information for the application of the time

- series

model.

The TSD lists the Lo gn orm al Probabilistic Dilution Model, Monte Car lo Simulation

Model and c ontinuous s imulation m odels. The EPA will consider such models submitted by the City when data to support them are available.

The permit is unchanged.

18. Comment: The ammonia value listed in Appendix E for ammonia on June 20, 2006, is 5.0 mg/L; however, the actual recorded value was 1.27 mg/L.

Response: The EPA cannot verify the comment. Changing the June 20, 2006 ammonia concentration from 5.0 mg/L to 1.27 mg/L d oes not change the determination of reasonable potential for ammonia for the seasonal period from November through April.

With the substitution of 1.27 mg/L for 5.0 mg/L t he City still has a reasonable potential to18

violate the water quality standards from November through April. The permit is unchanged.

19. Comment: The data used to calculate Reasonable Potential for copper needs to be

clarified. The Reasonable Potential Calculations and Limits calculations contained in

Table D

- 2 of the Fact Sheet indicate th at 60 samples were used in the calculation. The tables in Appendix E, pages 82

– 89 of the Fact Sheet, list 160 effluent values for copper from August 2003 through March 2013. Values listed between 8/31/03 and 3/31/08 are seemingly listed twice and there i s no value listed for 12/31/09 but there are two values

listed for 1/31/10.

Discounting duplicate entries, there are 116 available data points available on Fact Sheet pages 82

– 89. It is not clear which 60 samples were selected or the reason for their

se lection.

Because the Coefficient of Variation (CV) and the Reasonable Potential Multiplier (RPM) are determined from the selected data set, it is important that Puyallup both understand and have the opportunity to examine this data used for these calculations prior to adoption of the copper limitation.

Because of the selection of data points, differences in calculated values, and the methods used are not clear, Puyallup requests that EPA share the spreadsheet files used to make

the calculations for copper Reasonable Potential and Limits.

Response: The EPA agrees. There are duplicates in the tables for copper on pages 82 through 89 in Appendix E. Based on the DMRs t here are 116 data points between 8 /31/03

and 3/31/08 to calculate the reasonable p otential for copper as listed below.

7.2 ug/L 08/31/2003

11. ug/L 09/30/2003

10.6 ug/L 10/31/2003

9.8 ug/L 11/30/2003

10.5 ug/L 12/31/2003

12. ug/L 01/31/2004

9.7 ug/L 02/29/2004

8.1 ug/L 03/31/2004

10.7 ug/L 04/30/2004

10.8 ug/L 05/31/2004

13.4 ug/L 06/30/2004

6.1 ug/L 07/31/200419 11.8 ug/L 08/31/2004

. ug/L 09/30/2004

12.2 ug/L 10/31/2004

14.9 ug/L 11/30/2004

13.4 ug/L 12/31/2004

13.8 ug/L 01/31/2005

12.3 ug/L 02/28/2005

15.1 ug/L 03/31/2005

12. ug/L 04/30/2005

9.6 ug/L 05/31/2005

12.5 ug/L 06/30/2005

22.3 ug/L 07/31/2005

16.3 ug/L 08/31/2005

17.4 ug/L 09/30/2005

18.5 ug/L 10/31/2005

. ug/L 11/30/2005

15.6 ug/L 12/31/2005

10.1 ug/L 01/31/2006

13.1 ug/L 02/28/2006

13.2 ug/L 03/31/2006

14.2 ug/L 04/30/2006

16.4 ug/L 05/31/2006

18.4 ug/L 06/30/2006

20.9 ug/L 07/31/2006

14.6 ug/L 08/31/2006

13.8 ug/L 09/30/2006

14.9 ug/L 10/31/2006

17.9 ug/L 11/30/2006

12.4 ug/L 12/31/2006

9. ug/L 01/31/2007

15.5 ug/L 02/28/2007

11.7 ug/L 03/31/2007

12.7 ug/L 04/30/2007

4.5 ug/L 05/31/2007

3.7 ug/L 06/30/200720 3. ug/L 07/31/2007

3.1 ug/L 08/31/2007

5.5 ug/L 09/30/2007

6.5 ug/L 10/31/2007

4.2 ug/L 11/30/2007

6. ug/L 12/31/2007

3.9 ug/L 01/31/2008

4.3 ug/L 02/29/2008

5.2 ug/L 03/31/2008

2.8 ug/L 04/30/2008

2.6 ug/L 05/31/2008

2.9 ug/L 06/30/2008

3.4 ug/L 07/31/2008

2.8 ug/L 08/31/2008

2.9 ug/L 09/30/2008

2.8 ug/L 10/31/2008

4.1 ug/L 11/30/2008

4.2 ug/L 12/31/2008

4.3 ug/L 01/31/2009

3.2 ug/L 02/28/2009

2.8 ug/L 03/31/2009

3.7 ug/L 04/30/2009

4.4 ug/L 05/31/2009

3.9 ug/L 06/30/2009

2.6 ug/L 07/31/2009

3.8 ug/L 08/31/2009

4.2 ug/L 09/30/2009

7.7 ug/L 10/31/2009

3.4 ug/L 11/30/2009

5. ug/L 12/31/2009

7.7 ug/L 01/31/2010

5. ug/L 02/28/2010

4.9 ug/L 03/31/2010

7.5 ug/L 04/30/2010

4.4 ug/L 05/31/201021 2.7 ug/L 06/30/2010

3.1 ug/L 07/31/2010

3.8 ug/L 08/31/2010

4.2 ug/L 09/30/2010

5.2 ug/L 10/31/2010

6.4 ug/L 11/30/2010

4.9 ug/L 12/31/2010

4.9 ug/L 01/31/2011

4.4 ug/L 02/28/2011

4.8 ug/L 03/31/2011

8.1 ug/L 04/30/2011

6.4 ug/L 05/31/2011

6.3 ug/L 06/30/2011

4. ug/L 07/31/2011

4. ug/L 08/31/2011

3.5 ug/L 09/30/2011

6.7 ug/L 10/31/2011

6.1 ug/L 11/30/2011

5.4 ug/L 12/31/2011

5.9 ug/L 01/31/2012

6.1 ug/L 02/29/2012

5.9 ug/L 03/31/2012

4.8 ug/L 04/30/2012

5. ug/L 05/31/2012

3.4 ug/L 06/30/2012

5.9 ug/L 07/31/2012

5.2 ug/L 08/31/2012

5.2 ug/L 09/30/2012

4.8 ug/L 10/31/2012

4.3 ug/L 11/30/2012

5.6 ug/L 12/31/2012

6. ug/L 01/31/2013

5.9 ug/L 02/28/2013

6.9 ug/L 03/31/201322 116. Co unt

4.829 Standard Deviation

7.751 Average

0.623 CV

22.3 max

Using the 116 data points and u sing the same spreadsheet and the same equations provided in the Technical Support Document t he results lead to the same conclusion as is

in the fact sheet i.e. a reasonable potential to exceed water quality standards was found for copper. Using the same procedure as in the fact sheet t he resulting limits for copper were compared to effluent limits in the previous permit, with the more stringent limit s being selected for the new permit.

The copper CV and RPM are now determined from the same data set from 8/31/03 and 3/31/08 as provided by the City in their DMRs and stated in the comment. The procedures, methods and data set are clear and agree with th e City’s proposed data set.2324 Calculated Copper limits Using 116 data points Copper Limits

from Previous

Permit Limit for New

Permit

Average Monthly Limit (AML) 9.7 ug/L 8.5 ug/L 8.5 ug/L

Maximum Daily Limit 14.4 ug/L 13.7 ug/L 13.7 ug/L

Section 402(o) of the Clean Water Act and federal regulations at 40 CFR §122.44 (l) generally prohibit the renewal, reissuance or modification of an existing NPDES permit that contains effluent limits, permit conditions or standards that are less stringent than those established in the previous permit (i.e., anti

- backsliding) but provides limited exceptions. Section 402(o)(1) of the CWA states that a permit may not be reissued with

less

- stringent limits established based on Sections 301(b)(1)(C), 303(d) or 303(e) (i.e. water quality

- based limits or limits established in accordance with State treatment standards).

The more stringent copper limits are the limits in the previous permit which the Tribe has certified are protective and are therefore retained

.

The permit is unchanged.

20. Comment: Additionally, we contend that the copper and other metals limitations included in the existing permit are premised on erroneous data taken prior to 2002 not using ‘clean sampling methods’.

In June 2003, the City concluded a 12 month trace metals study using clean sampling methods (Wastewater Treatment Facility Trace Metals Study, February 2004, Gray & Osborne No. 02443). This study was presented to EPA and the Puyallup Tribe. Based on 21 sampling episodes it was f ound that there was no reasonable potential to exceed lead, mercury, and zinc water quality standards. EPA has drawn the same conclusion in the draft permit.

More importantly, the coefficient of variation (CV) for copper dropped to 0.29 and the

limits wer e recalculated by Puyallup using EPA’s permit level calculation methods. Using the new CV value, Puyallup believes its limits should have been established at 11.2 μg/L for the monthly average rather than the existing 8.5 μg/L. The values indicated on

page 50 of the Fact Sheet indicate an AML of 10.1 μg/L and a MDL of 14.4 μg/L, despite the draft permit limits remaining unchanged from the existing limits.

Following the study, in May 2004 letters were sent to EPA, the Puyallup Tribe, and the Department of Ec ology asking that limits for lead, mercury, and zinc be removed from Puyallup’s permit and that the copper limitation be revised.

When the City failed to receive a response, a letter was sent to Michael Li d gard, NPDES Permit Unit Manager, on January 25, 2 005, requesting that Puyallup’s permit be reopened and revised. The request met the requirements of 40 CFR 124.5 as it was in25

writing and contained facts and reasons supporting the request. There was no response to this request, as well.

Response : The EPA reevaluated the data as described in response to Comment No. 20 above. Based on that evaluation, EPA is retaining the existing limits because of prohibitions on backsliding. See Response to Comment 19.

21. Comment: EPA now promotes methodologies for determining copper limits that it considers improvements over the old EPA hardness

- based criteria used to establish Puyallup’s copper limitations. Hardness

- based criteria is used to establish limitations in both Puyallup’ s existing permit and its draft permit. The two methods promoted by EPA are the Biotic Ligand Model (BLM) for Copper and Streamlined Water

- Effects Ratio Procedure for Discharges of Copper (EPA

- 822

- R

- 01

- 005).

Puyallup requests that it be permitted to sub mit a test plan for use of the Biotic Ligand Model (BLM) and/or Water

- Effects Ratio testing for accurate determination of Puyallup’s effluent copper limitation.

Response: Federal regulatio ns at 40 CFR122.44 (vii) states:

“When developing water quality

- based effluent limits under this paragraph the permitting authority shall ensure that:

(A) The level of water quality to be achieved by limits on point sources established under this paragraph is derived from, and complies with all applicable wate r quality standards;...”

Copper water quality standards derived from a BLM or a water effects ratio are not the applicable water quality standards for copper. The applicable water quality standards are the current Puyallup Tribes water quality standards for copper

.

Some of the requirement s to make BLM and water effects ratio derived copper standards applicable to the water quality

- based effluent limits in the Puyallup NPDES permit are:

 Revising the Puyallup water quality standards

 Consultation with the U.S. Fish and Wildlife Service (USFWS) on revising the Puyallup standards

 Consultation with the National Marine Fisheries Service (NMFS) on revising the Puyallup standards

 EPA approval of the revision

The permit is unchanged.26

22. Comment: On December 4, 2013, HDR Engineering, Inc. completed a report reviewing different wastewater treatment technologies for their ability to meet discharge limits

associated with revised human health water quality criteria (HHWQC). HDR conducted

both a literature review of potential technologies and an engineering review of their capabilities to evaluate and screen treatment methods for meeting revised effluent limits

for four constituents of concern: arsenic, benzo(a)pyrene (BAP), mercury, and polychlorinated biphenyls (PCBs). Currently, there are no known facilities that treat to the HHWQC and anticipated effluent limits that are under consideration.

Among numerous other findings, HDR concluded that compliance with a HHWQC for

arsenic of 0.018 μg/L appears unlikely. Most treatment technology performance

information available in the literature is based on drinking water treatment applications targeting a much higher Safe Drinking Water Act (SDWA) maximum contaminant level (MCL) of 10 μg/L.

Response: This comment is outside the scope of the reissu ed permit since t he permit does not require treatment of arsenic, BAP, mercury or PCBs.

23. Comment: The 24 hour notification of violation requirement in Condition I.B.2. needs to be clarified to address circumstances where analytical results are not immediately available. As required in the draft permit, Puyallup may be placed in jeopardy of violating this requirement. For example, metals testing, for which there is a maximum

d aily limit, is analyzed for Puyallup by a commercial laboratory and the results are not available for two to three weeks after the sample is collected. The results, therefore, are not available within 24 hours of violation. Adding language to the draft per mit such as ‘...or within 24 hours of the analytical results being known....’ would correct this problem.

Response: This clarification is already in the permit, violations must be reported when the City becomes aware of the circumstances.

Condition I.B.2. states:

“ The permittee must report within 24 hours any violation of the maximum daily limits for all parameters for which there is a max daily limit in Table 1 above. Violations of all other effluent limits are to be reported at the time that discharge monitoring reports are submitted (See III.B. and III.H.). ”

However, F ootnot e 2 in Table 1 referring to 24 hour notification of a violation states:

“ 2. Reporting is required within 24 hours of a maximum daily limit or

instantaneous maximum limit violation. See Sections I.B.2. and III.G.”

Section III.G. clarifies the 24 hour reporting requirement:27 G. “ Twenty

- four Hour Notice of Noncompliance Reporting

1. The permittee must report the following occurrences of noncompliance by telephone within 24 hours from the time the permittee becomes aware of

the circumstances: (emphasis added)

... (d) a ny violation of a maximum daily discharge limitation for applicable pol lutants identified in Part I.B. ”

The permit is unchanged.

24. Comment: Additionally, because of the challenges associated with the maintenance and calibration of continuous monitoring pH instrumentation in a wastewater flow stream there is the potential for in stantaneous pH excursions, considered Daily Minimum or Daily Maximum violations, in the proposed permit. For example, an instantaneous or short duration 0.1 pH excursion above or below the minimum or maximum pH limit would technically be considered a viola tion and would need to be reported within 24

hours.

We believe it would be prudent and reasonable to place limits on the 24 hour reporting requirement in order to mitigate the potential for nuisance ‘emergency’ reporting of relatively inconsequential or short

- term limit excursions unlikely to have an advers e human health or environmental effect.

Response: Condition I.B.7. requires the use of methods that can achieve a ML less than

the effluent limitation. This requires the City to maintain and calibrate the continuous pH

instrumentation to monitor and ensure compliance with the pH limits

. Condition I.B.2.

does not require report ing within 24 hours of pH exceedances, only the toxic pollutants copper and ammonia . T his is clarified in the final permit.

Federal regulation at § 401.17 pH Effluent limitatio ns under continuous monitoring.

States:

“ (a) Where a permittee continuously measures the pH of wastewater pursuant to a requirement or option in a National Pollutant Discharge Elimination System (NPDES) permit issued pursuant to section 402 of the Act, the permittee shall maintain the pH of such wastewater within the range set forth in the applicable effluent limitations guidelines, except excursions from the range are permitted subject to the following

limitations: (1) The total time during which the pH values are outside the required range of pH values shall not exceed 7 hours and 26 minutes in any calendar month; and (2) No individual excursion from the range of pH values shall exceed 60 minutes. ”

T his exception to excursions are added to the permit.

Further, a s part of the reporting the City may provide information related to 40 CFR 133.102(c) that states:28

“ (c)pH. The effluent values for pH shall be maintained within the limits of 6.0 to 9.0

unl ess the publicly owned treatment works demonstrates that: (1) Inorganic chemicals are not added to the waste stream as part of the treatment process; and (2) contributions from industrial sources do not cause the pH of the effluent to be less than 6.0 or g reater than

9.0. ”

25. Comment: There appears to be an error in the WET testing requirements. In Condit i on I.C.4 the acute toxicity trigger is listed as 1 TUa. This should be 1.9 TUa based on the outfall dilution value cited throughout the Fact Sheet. We assume this is an error because there is no discussion or justification provided in the fact sheet. If the 1 TUa toxicity trigger is not an error, no basis has been provided for this change and therefore we request additional time to evaluate the impact of this change.

Also, t he draft permit only contains a trigger for accelerated testing for the annual acute

test. Under the current permit, accelerated chronic testing is required if the annual acute test exceeds the acute toxicity threshold.

Response: Permittees are typically only required to perform acute or chronic toxicity testing, depending on the dilution available for toxicity. Per EPA guidance at
EPA/505/2

- 90

- 001 at p. 58. , acute toxicity testing is recommended when the dilution of

the effluent is greater than 1000:1 at the edge of the mixing zone, and chronic toxicity testing is recommended when the dilution of the effluent falls below 100:1 at the edge of the mixing zone. The percentage effluent at the edge of the mixing zone is also referred

t o as the receiving water concentration (RWC). The mixing zone authorized by the Washington State Department of Ecology provides for a RWC of 52.6% effluent which is

1.9:1 . The refore the final permit will only require chronic toxicity testing. Acute toxicit y testing and the acute toxicity trigger in Condition I.C.4. are deleted from the final permit and all other references to acute toxicity monitoring is removed from the permit. The trigger for accelerated testing in condition I.C.4. is changed to 1 .9 TUc

.

26. Comment: Chronic Toxicity

– Under Puyallup’s existing permit, accelerated chronic toxicity testing is required when the no observable effects threshold (NOEC) exceeds 11.5 TUc (chronic toxicity units), which is equivalent to chronic toxicity observed in a test of diluted effluent at a concentration of 8.7% in river water or synthetic river water. This is the concentration at which there can be no effect on the survival, growth, or reproduction of the test organisms.

Under the draft permit there is both a survival endpoint and sublethal endpoints; however, there are no requirements listed for the chronic endpoints that would trigger accelerated testing. Additionally, the survival endpoint is listed as TUc = 100/NOECm meaning that

the threshold is exceede d if there is mortality of test organisms in 100% effluent. The draft also lists 52.6% effluent as being the dilution associated with the chronic toxicity trigger although no subsequent procedure is defined.

Response: The draft permit failed to provide t he necessary specificity regarding which chronic tests will be required. EPA will revise the final permit to specify that the chronic29

tests will be the fathead minnow larval survival and growth test (test method 1000.0 in

EPA

- 821

- R

- 02

— 013) and the ceriodap hnia dubia survival and reproduction test (test

method 1002.0 in EPA

- 821

- R

- 02

- 013). These test methods, and their endpoints, are identical to the test methods in the previous permit.

27. Comment: It is not clear whether any additional chronic tests are requi red under the draft permit if accelerated testing is triggered based on the annual acute test results. The current permit requires that a toxicity reduction evaluation (TRE) is initiated if an accelerated test exceeds a toxicity threshold, and further acce lerated testing can end if a

t oxicity i dentification e valuation ( TIE ) is also initiated. Under the draft permit, initiation of a TRE justifies ending the accelerated testing without the additional requirement of initiating a TIE.

Response: Acute testing i s no t r equired in the final permit

. The toxicity threshold is chronic toxicity. The final permit states the permittee may (emphasis added) initiate a TIE as part of the overall TRE p rocess

. T he permit also states if a TIE is initiated prior to completion of the accelerated testing, the accelerated testing schedule may be terminated, or used as necessary in performing the TIE.

28. Comment: Lastly, toxicity testing is performed for Puyallup by a laboratory recommended by the Department of Ecology that specializes in this type of testing. Unless the sampling and testing is conducted at the very beginning of a month, the results will not be available for submittal with the following month DMR.

Response: Reporting toxicity tests required Condition I.C.6.a ) is changed as follows:

The permittee must submit the results of the toxicity tests with the discharge monitoring reports (DMR) for the month following sample collection receipt of the results from the

lab.

29. Comment: The draft requires continuous tempera ture monitoring 100’ upstream of the plant outfall and 302’ downstream, respectively. The center of the outfall diffuser array is located about 70’ from the south river bank. To accurately monitor temperature representative of the downstream edge of the mi xing zone will require placement of a downstream monitoring station about 70’ from the south bank. The placement of the upstream station is likely less problematic because it does not need to be centered on the diffuser array as long as it is 100’ upstream and outside of influence of the diffusers.

Because of changes in surface elevation of as much as 20’, significant variations in flow between critical flow and extreme storm events, debris carried during storm events, and

shoulder

- to

- shoulder fishermen during salmon season, we believe it will be difficult to maintain, service, and recover data from the proposed continuous monitoring stations. The most practical time to access these locations for monitoring purposes is in the fall when the river is typic ally at its lowest.30

Puyallup is concerned about the time and complexity of meeting this requirement. In the absence of detailed guidance on how the City is expected to establish these monitoring stations, maintain the recording devices, and collect data f rom the devices, we recommend a monitoring requirement designed around temperature measurements taken during the critical flow time of the year when the potential for adverse effects are greatest and the ability to access equipment in the river is most pra ctical.

Response : The Puyallup Tribe’s temperature standard applies for the full year not just during low flow periods. The receiving water must be characterized for the year. Data loggers have been successful at another location storing a year of temper ature data during periods when access for recovery was not possible. During this period maintenance of the thermistors was not required. For example the TidbiT v2 Water Temperature Data Logger

- UTBI

- 001 has a battery life of five years and requires no oth er service according to Onset Hobo Data Loggers, maintains an accuracy of 0.2 o C and has a data logger with a capacity 42,900 hours or 4.9 years with the permit required 8,760 data points at one hour recording intervals.

Condition I.D.1. requires the City to w ork with the Puyallup Tribe to d evelop a receiving water monitoring plan. This plan must include a continuous temperature monitoring plan for both effluent temperature monitoring and surface water temperature monitoring. The Puyallup Tribe i s capable and experienced at providing the necessary guidance on locating temperature monitoring stations. The permit is unchanged.

30. Comment: Part II.D.9. seemingly is a redundant requirement because EPA and the Tribe will receive monitoring results throu ghout the term of the permit per II.D.10. However, the language of II.D.10 states that surface water monitoring results must be reported on the monthly Discharge Monitoring Report (DMR). DMR’s do not typically have a format easily accommodating data that i s only submitted quarterly or annually. Puyallup recommends that the reporting language in Part I.E.6. of Puyallup’s existing permit be retained and replace the language of the draft permit.

Response: Conditions II.D.9. and II.D.10 are not in the permit. However, Conditions I.D.9. and I.D.10 are in the permit and refer to submission of monitoring results. Condition I.E.6. of the previous permit states:

“ Receiving water monitoring results must be submitted to the EPA and the Puyallup Tribe Environmental Department with the January Discharge Monitoring Report. ”

Condition I.D.9 requires submission of the monitoring reports with the monthly DMRs

for the EPA to ensure in a timely manner the City is conducting the monitoring with out waiting until the end of the year. DMRs are used for submission of quarterly results from

ot her permittees without problems and will be used without problems for the City’s reporting.

31. Comment: We assume that the required Toxic Organic Sampling under Condition II.A.8.i) will satisfy a portion of the required sampling under Part I.B.9, pg. 8, but would31

like clarification. Additionally, Puyallup requests that language be added ...once during the cycl e of this permit... for clarification of when and how often the Toxic Organics Sampling must be performed during the permit cycle.

Response: The toxic organic sampling requirement i n Condition II.A.8.i) of the

pretreatme nt requirements can satisfy a portion of the required sampling required under

Part I.B.9

, effluent testing required by Part D of NPDES application Form 2A

, which

states:

“ To the extent that effluent monitoring required by other conditions of this permit satisfies this requirement, these sam ples may be used to satisfy the requirements of this paragraph.”

Toxic organic sampling is required once per year for the following reasons :

 To characterize the discharges for toxic organic discharges.

 To determine if a local limit study is needed

 To identify treads in toxic organic discharges and inflow

A toxic organic sampling frequency of once per year is added to the permit.

32. Comment: The language of Condition II

. F. Emergency Response and Public

Notification Plan is too broad making interpretation difficult and potentially leading to the requirement for public notification for events that have little or no health or environmental effects. While we feel public notification is a reasonable addition to the draft permi t, the language needs to be clarified and the notification requirements better defined so that it does not result in unnecessary notifications that serve no greater good.

For example, is the ‘Plan’ only invoked in the event of an unanticipated bypass or overflow or is it also invoked at any time any effluent limitation in the permit is exceeded as stated in the draft permit? Is the language applicable to instantaneous pH excursions, monthly or weekly violations of BOD 5 , TSS, copper or other such results t hat may have little or no health or environmental effects or in situations where the violation only becomes evident after the event has transpired?

T he language of Part II.F. is sensible in the context of a discharge that is immediately dangerous to hu man health or the environment but it does not make sense in the context of exceeding “any effluent limitation in the permit...” such as BOD5, TSS, copper or other such results that may have little or no health or environmental effects or the violation only becomes evident after the event has transpired?

Response: T he plan and public notice is only for “ an overflow

... that may endanger health and unanticipated bypasses or upsets that exceed any effluent limitation in the permit. ” Public notification is not required any time any effluent limitation in the permit32

is exceeded , only those that exceed an effluent limitation due to an unanticipated bypass or upset or an overflow that may endanger health.

The permit is unchanged.

33. Comment: Conditi o n III.I

., Public Notification refer ence t o Part II.G. is erroneous and

should reference Part II.F.

Response: The EPA agrees. The reference is changed to Part II.F.