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 applicatio n 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 th e 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 mon itoring records and reports resubmitted to the Department by the permittee; and

• That the discharge is consistent with applicab le effluent standards a nd limitations, water quality standards, and other legally applicable requireme nts 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 pe rmit, which Ecology proposes to reauthorize to

Chambers Creek Wastewater Treatment Plant for the discharge of wastew ater to Puget Sound. The previous fact sheet is also part of this administ rative 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. Si nce the issuance of the previous permit, Ecology has not received any

information which indicates that environmental im pacts from the discharge have changed. The reauthorized permit is similar to the prev ious 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 stri ngent 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 reauthor izing 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 co mpleted and submitted and do not require additional or continued assessment were removed from this pe rmit. The submittal dates for the other standard compliance and submittal requirements that have b een carried over from the past permit into this reauthorized permit have been adjusted to the pro posed permit schedule. Ecology considered these submittals necessary in the previous permit an d 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 efflue nt limits. However, Ecology has examined the discharge monthly monitoring reports (DMRs), pr iority 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

Page 2Addendum 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 capac ity 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 efflue nt 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 W ET. 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 dieldr in 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 Pars hall flume. However, the facility routes internal flow from the fertilizer plant centrifuge, to the head works upstream of the flow meter. Ecology is requiring the County to relocate the recycle streams dow nstream 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 in fluent monitoring with dates for the plan and final

construction.

Public notice of the availability of the draft reauthor ized 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).

Page 3Addendum

For NPDES Perm to the Fact Sheet

it No. WA0039624

Page 4 After the public comment period has closed, Ecology will summarize the substa ntive 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 summa rized in the fact sh eet addendum, Appendix D— Response

to Comments

.

IV. RECOMMENDATION FOR PERMIT ISSUANCE

Ecology proposes that this permit be issued for five years.to the Fact Sheetit No. WA0039624Page 5Max concentration atedge of...AcuteMixingZoneChronicMixingZoneLIMITREQ'D?EffluentpercentilevalueMultiplierParamug/L ug/LPnsCopper0 0 41.69 0.52 NO 0.95 0.8830.741.40 18 112 AmCommencement Bay 95th%ilCALCULATIONSState Water QualityStandardMetal CriteriaTranslator asdecimalMetal CriteriaTranslator asdecimalAmbientConcentration(metals asdissolved)Acute ChronicMax effluentconc.measured(metals as totalrecoverable)CoeffVariation# ofsamplesAcuteDil'nFactorChronicDil'nFactoreterAcute Chronicug/L ug/L ug/Lug/L CVnCOMMENTS0.83 ..83 .240 .8000 3.100022.850.8524bient value fromeRevised 3/00LIMITREQ'D?AVERAGEMONTHLYEFFLUENTLIMITMAXIMUMDAILYEFFLUENTLIMITMultiplierDilutionFactorParameteMercury0.85 1.001.8000 0.0250 0.00 0.00 NO 0.95 0.368 0.00560.55 3 3.00 18 112Ammonia NH3-N1.00 1.00 20.0000 7612.0000 1143.0000 1524.71 264.52 NO 0.95 0.994 44400.00000.55 502 0.62 18 1120.600.60This spreadsheet calculates the reasonable potential to exceed state water quality standards for a small number of samples. Theprocedure and calculations aredone 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. Userinput columns are shown with red headings. Corrected formulas in col G and H on 5/98 (GB)AmbientConcentration(Geometric Mean)Maxeffluentconc.measuredCoeffVariationrug/Lug/Lug/L Cug/Lug/Lug/LPnVSDieldrin0. 4 0.00001NO1NONE NONE0.86 0 001.20.27 0.0015 112.0Heptachlor0.00 0.00021 0.00001NO1NONE NONE0.86 0.09001.4 20 0.21 0.0015 112.0Maxconcentration atedge of chronicmixing zone.dtileonc.10)ExpectedNumber ofComplianceSamples perMonthn0.0000010.50.051.85200.502.57Water QualityCriteria forProtection ofHumanHealthCalculate50thpercenEffluent C(When n># ofsamplesfromwhich #in col. KwastakenEstimatedPercentile at95%ConfidenceAquatic Life Reasonable PotentialHuman Health Reasonable PotentialAddendumFor NPDES PermAddendum to the Fact Sheet

For NPDES Permit No. WA0039624

APPENDIX A – PUBLIC INVOLVEMENT INFORMATION

Ecology has determined to reauthorize a discharge pe rmit 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 heari ng 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 pr oposed 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 environm ental protection, permit conditions, or any other concern that would result from reauthorization of this permit.

Ecology will consider all comments re ceived 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.

Page 6Addendum 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 work ing on a facilities plan to increase the plant capacity.

Response 1 :

Ecology has noted this future expansion and may up date 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 clarifie r 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 understa nds 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 assume s 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.

Page 7