ADDENDUM TO THE FACT SHEET 

FOR THE 2008 REAUTHORIZATION 

FOR NATIONAL POLLUTANT DISCHARGE 

ELIMINATION SYSTEM (NPDES) 

PERMIT NO. WA0039624 

I. GENERAL INFORMATION 

Facility: Chambers Creek Wastewater Treatment Plant 

10311 Chambers Creek Road 

University Place, WA 98467 

II. APPLICATION REVIEW 

Pierce County submitted an application for permit reissuance was submitted to the Department of 

Ecology (Ecology) on June 29, 2007, and July 23, 2007, and Ecology accepted it on July 24, 2007. The 

scope and manner of any review of an application for replacement of permit by Ecology shall be 

sufficiently detailed as to insure the following: 

• That the Permittee is in substantial compliance with all of the terms, conditions, requirements 

and schedules of compliance of the expired permit; 

• That Ecology has up-to date information on the Permittee’s waste treatment practices; nature, 

content, and frequencies of Permittee’s discharge; either pursuant to the submission of new 

forms and applications or pursuant to monitoring records and reports resubmitted to the 

Department by the permittee; and 

• That the discharge is consistent with applicable effluent standards and limitations, water quality 

standards, and other legally applicable requirements listed in Washington Administrative Code 

(WAC) 173-201A and WAC 173-221. 

Ecology reviewed the application for Chambers Creek Wastewater Treatment Plant and determined that 

no substantial changes in the treatment characteristics of the effluent process or volume of wastewater 

has occurred. 

III. PERMIT REAUTHORIZATION 

This fact sheet addendum accompanies the draft permit, which Ecology proposes to reauthorize to 

Chambers Creek Wastewater Treatment Plant for the discharge of wastewater to Puget Sound. The 

previous fact sheet is also part of this administrative record and explains the basis for the discharge 

limitations and conditions of the reauthorized permit. 

The existing permit requirements, including discharge limitations and monitoring, do not need to be 

changed substantially to protect the receiving water quality. The previous fact sheet addressed 

conditions and issues at the facility at the time the previous permit was issued, and statements made 

reflected the status in 1999. Since the issuance of the previous permit, Ecology has not received any 

information which indicates that environmental impacts from the discharge have changed. The 

reauthorized permit is similar to the previous permit issued on December 2, 2002. 
Addendum to the Fact Sheet 

For NPDES Permit No. WA0039624 

The discharge limits and conditions in effect at the time of expiration of the previous permit are carried 

over largely unchanged to this reauthorized permit. Assessment of compliance and inspections of the 

facility during the previous permit term indicate that the facility should not be placed on a high priority 

for permit renewal. Ecology assigns a high priority for permit renewals in situations where water 

quality would materially benefit from a more stringent permit during the next five-year cycle. 

The permit reauthorization process, in concert with the routine renewal of high priority permits, allows 

Ecology to reissue permits in a timely manner and minimize the number of active permits that have 

passed expiration dates. A system of ranking the relative significance of the environmental benefit to be 

gained by renewing a permit rather than reauthorizing a permit is followed during Ecology’s annual 

permit planning process. Each permit that is due for reissuance is assessed and compared with other 

permits that are also due for reissuance. The public is notified and input is sought after the initial draft 

ranking has tentatively established which permits are likely to be completely renewed and which are 

likely to be reauthorized. All relevant comments and suggestions are considered before a final decision 

is made regarding the type of reissuance for each permit. 

One of the changes to the previous permit includes the submittal date requirements. Submittal 

requirements from the previous permit that were completed and submitted and do not require additional 

or continued assessment were removed from this permit. The submittal dates for the other standard 

compliance and submittal requirements that have been carried over from the past permit into this 

reauthorized permit have been adjusted to the proposed permit schedule. Ecology considered these 

submittals necessary in the previous permit and no information has come forward to cause a 

reconsideration of the submittal requirement. 

The Chambers Creek wastewater treatment facility changed little over the last permit cycle. Ecology 

proposes no major changes to the permit or effluent limits. However, Ecology has examined the 

discharge monthly monitoring reports (DMRs), priority pollutant scans, and studies conducted by 

Chambers Creek over the last permit cycle. This fact sheet addendum includes specific information on 

the following topics: 

• Dilution factors 

• Aquatic life reasonable potential for select metals and ammonia 

• Plant capacity rating examination 

• Chlorine Limits for algae and filamentous control 

• Whole Effluent Toxicity (WET) testing 

• Human Health Reasonable Potential for dieldrin and heptachlor 

• Influent flow monitoring 

Dilution Factors 

Chambers Creek conducted a new dilution analysis in 2006 which predicted an increased acute dilution 

factor and decreased chronic dilution factor. As part of that analysis, Chambers Creek conducted a dye 

study to examine their dilution and calibrate the existing dilution modeling. Ecology reviewed and 

approved the dilution analysis report. The new dilution factors are included below: 

Old Dilution 

Factors 

New Dilution 

Factors 

Acute Dilution 16.7 18.2 

Chronic Dilution 168 112 

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Addendum to the Fact Sheet 

For NPDES Permit No. WA0039624 

Ecology removed the requirement to submit a mixing zone plan of study and removed the requirement 

to submit an effluent mixing report because Chambers Creek completed these items. 

Aquatic Life Reasonable Potential 

Ecology conducted a new reasonable potential analysis of the metals and ammonia using the new 

dilution factors and data collected over the last two permit cycles. Ecology found no reasonable 

potential for the metals or ammonia to violate water quality standards. 

Plant Capacity 

Chambers Creek operates at near 85 percent of capacity and plans to add capacity in the near future. 

Chambers Creek completed a facility re-rating and optimization study in 2005 which showed some 

bottlenecks to achieving full capacity. These bottlenecks were mainly in the secondary clarifiers and 

UV treatment system. Ecology has not changed the design capacity in permit section S4. If Chambers 

Creek completes major modifications to the plant that increase the plant design capacity, Ecology will 

modify or reissue the permit. 

Chlorine Use and Limits 

Chambers Creek disinfects the effluent with UV light. However, the facility adds chlorine to the 

clarifier, at times, and to the UV basin frequently, to control algae growth. Ecology changed the permit 

so that the Permittee must now test for chlorine in the effluent whenever chlorine is used. 

Whole Effluent Toxicity (WET) 

The permit will continue to have a limit for acute WET. The effluent showed toxicity. The samples 

showed the median survival in 100 percent effluent at less than 80 percent; as a result, Ecology believes 

that there is a reasonable potential to violate the WET effluent limit. 

Human Health Reasonable Potential 

Chambers Creek measured detectable levels of dieldrin and heptachlor in several effluent samples. 

These pesticides were banned by EPA, are persistent and are likely showing up as residue of previous 

activity. Ecology found no reasonable potential to exceed water quality standards for the protection of 

human health for these pollutants. 

Influent Flow Monitoring 

Chambers Creek monitors influent flow with a Parshall flume. However, the facility routes internal 

flow from the fertilizer plant centrifuge, to the headworks upstream of the flow meter. Ecology is 

requiring the County to relocate the recycle streams downstream of the flow meter or alternatively, it 

can measure the recycle flow and subtract it from the compounded flow. A new section S12 requires 

Chambers Creek to submit a plan to ensure proper influent monitoring with dates for the plan and final 

construction. 

Public notice of the availability of the draft reauthorized permit is required at least 30 days before the 

permit is issued WAC 173-220-050. The fact sheet and draft permit are available for review (see 

Appendix A—Public Involvement for more detail on the Public Notice procedures). 

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Addendum

For NPDES Perm

 to the Fact Sheet 

it No. WA0039624 

Page 4 

After the public comment period has closed, Ecology will summarize the substantive comments and the 

response to each comment. The summary and response to comments will become part of the file for the 

permit and parties submitting comments will receive a copy of Ecology’s response. Comments and the 

resultant changes to the permit will be summarized in the fact sheet addendum, Appendix D—Response 

to Comments. 

IV. RECOMMENDATION FOR PERMIT ISSUANCE 

Ecology proposes that this permit be issued for five years. 
 to the Fact Sheet 

it No. WA0039624 

Page 5 

Max concentration at 

edge of...

Acute 

Mixing 

Zone

Chronic 

Mixing 

Zone

LIMIT 

REQ'D?

Effluent percentile value Multiplier

Param ug/L ug/L Pn s

Copper 0 0 4 1.69 0.52 NO 0.95 0.883 0.74 1.40 18 1

CALCULATIONS

State Water Quality 

Standard

Metal Criteria 

Translator as 

decimal

Metal Criteria 

Translator as 

decimal

Ambient 

Concentrati

on (metals as 

dissolved) Acute Chronic

Max effluent 

conc. 

measured 

(metals as total 

recoverable)

Coeff 

Variation

# of 

samples

Acute 

Dil'n 

Factor

Ch

D

Fa

eter Acute Chronic ug/L ug/L ug/L ug/L CV n 

0.83 ..83 .240 .8000 3.1000 22.85 0.85 24 

Revised 3/00

LIMIT 

REQ'D?

AVERAGE 

MONTHLY 

EFFLUENT 

LIMIT

MAXIMUM 

DAILY 

EFFLUENT 

LIMIT 

Paramete

Mercury 0.85 1.00 1.8000 0.0250 0.00 0.00 NO 0.95 0.368 0.0056 0.55 3 3.00 18 1

Ammonia NH3-N 1.00 1.00 20.0000 7612.0000 1143.0000 1524.71 264.52 NO 0.95 0.994 44400.0000 0.55 502 0.62 18 1

0.600.60

This spreadsheet calculates the reasonable potential to exceed state water quality standards for a small number of samples. The procedure and calculations are done per the procedure in Technical Support Document for Water Quality-based Toxics Control, U.S. EPA, March, 1991 (EPA/505/2-90-001) on page 56. User 

input columns are shown with red headings. Corrected formulas in col G and H on 5/98 (GB)

Ambient 

Concentration 

(Geometric Mean)

Max 

effluent 

conc. 

measured

Coef

Variati

r ug/L ug/L ug/L ug/L ug/L Pn ug/L CV 

Dieldrin 0. 4 0.00001 NO 1 NONE NONE 0.86 0 00 

Heptachlor 0.00 0.00021 0.00001 NO 1 NONE NONE 0.86 0.0900 

Max 

concentration at 

edge of chronic 

mixing zone.

Expected 

Number of 

Compliance 

Samples per 

Month

0.00 0001 0.50 .05 1.85 

0.50 2.57

Water Quality 

Criteria for 

Protection of 

Human 

Health

Estimated Percentile at 95% Confidence

Aquatic Life Reasonable Potential Human Health Reasonable Potential AddendumFor NPDES Perm
Addendum to the Fact Sheet 

For NPDES Permit No. WA0039624 

APPENDIX A – PUBLIC INVOLVEMENT INFORMATION 

Ecology has determined to reauthorize a discharge permit to the applicant listed on page 1 of this fact 

sheet addendum. The permit contains conditions and effluent limitations that are described in the fact 

sheet. 

Public notice of application was published on June 20, 2007, and June 27, 2007, in Tacoma News Tribune

to inform the public that an application had been submitted and to invite comment on the reauthorization 

of this permit. 

Ecology will publish a Public Notice of Draft (PNOD) on April 15, 2008, in Tacoma News Tribune to 

inform the public that a draft permit and fact sheet are available for review. Interested persons are invited 

to submit written comments regarding the draft permit. The draft permit, fact sheet addendum, and fact 

sheet are available for inspection and copying between the hours of 8:00 a.m. and 5:00 p.m. weekdays, by 

appointment, at the regional office listed below. Written comments should be mailed to: 

Carey Cholski 

Department of Ecology 

Southwest Regional Office 

P.O. Box 47775 

Olympia, WA 98504-7775 

Any interested party may comment on the draft permit or request a public hearing on this draft permit 

within the 30-day comment period to the address above. The request for a hearing shall indicate the 

interest of the party and the reasons why the hearing is warranted. Ecology will hold a hearing if it 

determines there is a significant public interest in the draft permit (WAC 173-220-090). Public notice 

regarding any hearing will be circulated at least 30 days in advance of the hearing. People expressing an 

interest in this permit will be mailed an individual notice of hearing (WAC 173-220-100). 

Comments should reference specific test followed by proposed modification or concern when possible. 

Comments may address technical issues, accuracy and completeness of information, the scope of the 

facility’s proposed coverage, adequacy of environmental protection, permit conditions, or any other 

concern that would result from reauthorization of this permit. 

Ecology will consider all comments received within 30 days from the date of the PNOD indicated above, 

in formulating a final determination to issue, revise, or deny the permit. Ecology’s response to all 

significant comments is available upon request and will be mailed directly to people expressing an 

interest in this permit. 

Further information may be obtained from Ecology by telephone at 360-407-6279 or by writing to the 

address listed above. 

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Addendum to the Fact Sheet 

For NPDES Permit No. WA0039624 

APPENDIX B – RESPONSE TO COMMENTS 

Comments from Pierce County Chambers Creek 

Comment 1: 

Plant Capacity—Pierce County is currently working on a facilities plan to increase the plant 

capacity. 

Response 1: 

Ecology has noted this future expansion and may update the permit and limits as needed after the 

upgrade occurs. 

Comment 2: 

Chlorine Use and Limits—Pierce County assumes this to mean when chlorine is introduced into 

the final effluent, either at the secondary clarifier launder, or at the confluence of the UV system 

effluent channels. Our standard operating procedures now include testing for chlorine in the 

effluent when chlorine is used to backup the UV system and when chlorine is introduced to the 

secondary clarifier weirs for algae controls. 

Response 2: 

Ecology thinks this is correct. No change is needed to the permit. 

Comment 3: 

Influent Flow Monitoring—Pierce County understands Ecology’s request to relocate the recycle 

streams downstream of the influent flow or alternatively measure the recycle flows and subtract it 

from the compounded flow. Peirce County will submit a plan to ensure proper influent 

monitoring with dates for the plan and final construction. 

Response 3: 

Ecology thinks this is correct. No change is needed to the permit. 

Comment 4: 

S2 Monitoring Requirements—Monitoring Schedule—effluent ammonia minimum sampling 

frequency was left blank. Pierce County assumes the current permit sampling frequency will be 

continued. 

Response 4: 

Ecology agrees and will fix the table to show the ammonia on the monitoring schedule. 

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