## FACT SHEET FOR NPDES PERMIT WA0039624 PIERCE COUNTY CHAMBERS CRE EK WASTEW ATER FACILITY

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

TABL E OF CONTENTS

INTRODUCTION

................................................................................................................... ..................... 1

BACKGROUND INF O RMATION

......................................................................................................... .... 2 DESCRIPTION OF THE FACILITY

............................................................................................. 2 History

........................................................................................................................ ........ 2 Collection S y stem Status

.................................................................................................... 2 Treat ment Pr ocesses

........................................................................................................... 2 Industrial Discharges

.......................................................................................................... 4 Discharge Ou tfall

.............................................................................................................. .. 4 Residual Solids

................................................................................................................ ... 4 PERMIT STATUS

.................................................................................................................. ......... 5 SUMMARY OF COMPLIANCE WITH THE PREVIOUS PERMIT

............................................ 5 WASTEWATER CHARACTERIZAT ION

.................................................................................... 5 SEPA COMP LIANCE

................................................................................................................ ..... 5

PROPOSED PERMIT LIMITATIONS

.................................................................................................... .... 5 DESIGN CRITERIA

................................................................................................................ ....... 6 TECHNOL OGY-BASED EFFLUENT LIMITATIONS

................................................................ 6 SURFACE WATER QUALITY-BASED EFFLUENT LIMITATIONS

........................................ 7 Nu m e rical Criteria for the Protection of Aquatic Life

........................................................ 7 Nu m e rical Criteria for the Protection of Hu m a n Health

..................................................... 8 Narrative Criteria

............................................................................................................. ... 8 Antidegradation

................................................................................................................ .. 8 Critical Conditions

............................................................................................................ .. 8 Mixing Z one s

................................................................................................................... ... 8 Description of the Receivi ng Water

.................................................................................... 8 Surface Water Qua lity Criteria

........................................................................................... 9 Consideration of Surface Water Qualit y - Based Lim i ts for Numeri c Criteria

..................... 9 Whole Effluent Toxicit y

................................................................................................... 12 Hu m a n Health

................................................................................................................... 13 Sedi m e nt Quality

.............................................................................................................. 1 3 GROUND W A TER QUALITY LIMITATIONS

.......................................................................... 13 COMPARIS ON OF EFFL UENT LIMITS WITH THE EXISTING PERMIT ISSUED March 28, 1990.

................................................................................................................ 13 MONITORING requirements

........................................................................................................ ............. 14 LAB ACCREDITATION

.............................................................................................................. 14

OTHER PERMIT CONDI TI ONS

........................................................................................................ ...... 15 REPORTING AND RECORDKEEPI NG

..................................................................................... 15 PREVENTION OF FACI L I TY OVERL OADI NG

....................................................................... 15 OPERATION AND M A I N TEN ANCE (O&M)

............................................................................ 15 RESIDUAL SOLIDS HANDLING

............................................................................................... 15 PRETREAT M ENT

................................................................................................................... ..... 15 SPILL PLAN

..................................................................................................................... ............ 15 EFFLUENT MIXI NG ST UDY

..................................................................................................... 16 OUTFALL E VALUATION

.......................................................................................................... 16 GENERAL CONDITIONS

........................................................................................................... 16

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

PERMIT ISSUANCE P R OCEDURES

..................................................................................................... . 16 PERMIT MODIFICATIONS

........................................................................................................ 16 RECOMME NDATI ON F O R PERMIT ISSUANCE

.................................................................... 16

REFERENCES FOR TEXT AND APP E NDICES

..................................................................................... 17

APPENDI X A--PUBLIC I NVOL VE M E NT INFORMATION

................................................................. 18

APPENDIX B--GLOSSARY

........................................................................................................... .......... 19

APPENDIX C--TECHNICAL CALCULATIONS

.................................................................................... 24 Summary of Cham ber Creek Outfall Eval uation from ReRating Investigation

............................ 28 Am bient Velocity Near Cham ber Creek WWTP Out f all

.............................................................. 28 Current Condition

.............................................................................................................. ............ 28 Summary of Mixing Z one Evaluation Cr itical Conditi on Criteria

................................................ 28 Parameter

...................................................................................................................... .... 28 Desc ription 1

...................................................................................................................... 28 Source

......................................................................................................................... ...... 28 Acute

.......................................................................................................................... ....... 28 Chronic

........................................................................................................................ ..... 28 Outfall Diffuser Input Parame ters for PLUMES Model

................................................................ 28 Criteria

....................................................................................................................... ....... 28 Summary of Critical Conditions

................................................................................................. ... 29 Parameter

...................................................................................................................... .... 29 Description

.................................................................................................................... .... 29 Acute

.......................................................................................................................... ....... 29 Chronic

........................................................................................................................ ..... 29

APPENDIX D--RESPONSE TO COM M ENTS

........................................................................................ 31

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

INTRODUCTION

The Federal Clean Water Act (FCWA, 1972 , and late r m odifications, 197 7, 19 81, and 1 987 ) established water quality goals for the navigable (surface) water s of the United States. One of the mechanism s fo r achieving the goals of t h e Clean Water Act is the National Poll utant Discharge Elim inati on S y stem (NPDES) permit, which is ad m i nistered by the Envi ronm ental Protection Agency (EPA). The EPA h a s delegated responsibility to ad m i nist er the NPDES permit program to the state of Washington on the basis of Chapter 9 0 .48 Revised Code of W ashington ( RCW) which defines the Department of Ecolog y ' s (Depart m ent) authority and obligations in adm i nist eri ng the wastewater dischar ge per m it progra m

. The regulations adopted b y the state include proce dur es for issuing perm its [ C hapter 173-2 20 Washington Ad m i nistrative Code (WA C ) ] , t echnica l criteria for discharges f r om municipal wa stew ate r treat men t facilities (Ch a pter 173-221 WAC), water qualit y cr ite ria for surface and ground waters (Chapters 173- 201A and 200 WAC), and sedi m ent m a nagem e nt sta ndards (Chapter 173-204 WAC). These regulations require that a perm it be issued before discharge of w aste w ate r t o waters of the state i s al lowed. The regulations also establish the basis fo r effluent lim itations an d other requ irem ents which are to be included in the perm it. One of the requirem e nt s (WAC 173-220-06 0) for issuing a permit under the NPDES per m it progra m is the prepar ation of a dr aft per m it an d an ac co m p any i ng fact s h eet. Public notice of the availability of the draft permit is require d at least 30 day s before the per m it is i ssued (WAC 173-220-050) . The fact sheet and dr aft per m it ar e a v a i l a b l e f o r r e v i e w ( s e e A p p e n d i x A

- - P ub l i c Involvem e nt of the fact sheet for m o re detail on the Public Notice procedures). The fact sheet and draft perm it have bee n reviewed by the Per m itt ee. Errors an d om is sions identified in this review h a ve been corrected before going t o pu blic notice. After the public co mment period has closed, the D e part m e nt wi ll su mmariz e the substant ive co mment s and the r e s ponse to eac h co mment. The summary and response to comments will become pa rt of the fil e on the permit and parties subm itting
co mments will receive a copy of t h e Depart men t ' s response. The fact sheet will not be revised

. Co mments and the result ant changes to the perm it will be summarized in Appendix D- -Response to Co mments.

GEN E RA L INFORMAT ION Applicant Pierce County, Publ ic Wor k s and Utiliti es 9850 Cham bers Creek Road University Pl ace, WA 98467-1040 Facility Name and Address Cham bers Creek Regional WWTF 1031 1 Chambers Creek Road University Pl ace, WA 98467-1040 Type of Treatment: Activated Sludge Secondary Treatm e nt Discharge Lo cation Puget Sou n d Latitude: 47° 11' 41.5" N Longitu de: 1 22° 35' 2.1" W. Water Body I D Nu m b er 25-00- 02

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

BAC K GROUND I N FORMATI O N

DESCRIPTION OF THE FACILITY

H ISTORY Located in the City of University Place, the Cham bers Creek Reg i onal Wastewater Tr eat ment Facility WWTF serves m o re than 65,000 households and 2, 000 businesses in the cities of DuPont , Lakewood, Taco m a , University Place, the Town of Steilaco om , and unincorporated areas such a s Parkland, Spanaway , Fr ederickson, and So uth Hill

. Ground water quality pro b l e m s had been docum ented in the Cham bers Creek Basin as early as 1939 . The groun d water problem s were attributed to a high num b e r of failing on-site septic sy stem s within the urban areas of the Cha m bers Cr eek Basin. In 1970, state and local health departme nt officials banned septic installation within t h e basin and design and constr u c tion of t h e Cham bers Creek Regional Wastewater Facility bega n in 1977. T h e Pierce Co unty sewer system became full y operational with the opening of the Cham bers Creek WWTF in 19 84.
The Cham bers Creek Regional WWTF began operating in November 1984 with a rated capacity of 12 MGD average dry weather flow. The facility was upgraded in 1992-1995 and 1998-1999 and currently has a rated maxim u m m o n t h flow of 2 8

. 7 MGD.

C OLLECTION S YS TEM S TATUS
The collection s y stem includes approx im ately 564 miles of pipe, 12,7 00 manholes, 90 main pum p stations, and five odor c ontrol faciliti es. There are 77 pum p stations that have permanent backu p generators in case of power outages with six portabl e generators to service the re m a ini ng 13 pum p stations. In addition to t h e 90 main pum p statio n s the Cha m b e rs Cr eek W W TF is resp onsible for maintaining 8 36 residential grinder p u mps in the Pier ce County area. The County has three ful l -time em ploy ees specifically for infil t ration and inflow reduction with an approxim a te annual bu dget of $4 50, 000

. T REATMENT P ROCESSES Wastewater enters the Cham b e rs Creek Regional Wastewater Facility thro ugh a 72-inch gravity line int o an energy dis s ipater. From the energy dissipater flow runs to th e head or di version bo x and is directed to three step s c reens with 1⁄4 inch sp acing. There ar e also three rota ry screens with 1/10 inch spacing available for backup. Three step screens separate larger nonsoluable solid s in the wastewat er. These screens collect solids using m e tal p l ates that wa s t ewater pa sse s through. D e bris in the waste w ate r c o llects agains t the plates, which step up periodicall y to m ove the debris to a c onve y o r belt th at transports it to a washer/co m pactor. In the washer /co m pactor, organics are w ashed out of th e scre e nings and returned to the treat me nt process

. The co m p act or rem oves excess water f r om the remaining debris, which is convey e d t o a dum p st er and disposed in a sanitary landf ill. Three grit tan k s use air dif f users to ke e p m o st of the solids suspe nded in the w aste wat e r w h ile allowing heavier m o stl y inorganic matter, such as sand and grit, to settle t o the bottom of the tank. The sand and grit is conve yed to a dum pster then dispo sed in a sanitary landfi ll.

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility
Following gr it rem oval, wastewater passes through a 6 -foot wide Parshall flu m e, where the am ount of waste w ate r entering the plant is m e as ured. After flow is m e asured, wast ewater enter s the prim ary influent chan nel, from which it is distrib u ted am ong the prim ary cl arifiers. Six prim ary sedi m entation tanks are plac ed into service by the operation staff on an as need ed basis. Th e influent flow rate governs the num ber of prim ary sed imentation t a nks operating at an y tim e. Tanks are 114 feet lon g , 41.5 feet wide, with an 8.5 feet side water depth. A flight and chain m echa n is m is used to collect set t a ble solids (pri m a ry sludge) fro m the b o ttom of the tanks. Prim ary slud ge is pum ped to gravity belt thickeners and t h en is pum pe d to the solids digesters

. Floatable solids (prim a ry scu m ) are pum p e d to a rotary fine screen at the head works. Screenings are taken to a sa nitary landfill . Wit h settleable solids an d scum rem o ved, prim ary effluent flows to the first stage of seco ndary treatme nt. Secondary tr eatment begins with bioselectors used to propagate the bacteria in the wastewater that are
m o st beneficial in breakin g down orga nics. Currently there are five bioselector basins. Each basin is divided i n to s i x sections. Baffle walls inside the basi ns create a s e ries of selecto r and aeration cells. Four are anoxic (onl y enou gh a i r is added for m i xing to occu r so that the growth of filam e ntous bacteria is constrained) and two are oxic (large quantities of air are diffused through the w astewater to maxi m i ze the
am ount of oxygen availabl e to the proc ess bact eria). In each basin, som e of t h e m i xed liquor from the oxic zone is recy cled to anoxic zones one and three. From the oxic cells of each bioselector basin, m i xed liquor fl ows into the m i xed liquor channel where it is conve y e d to t h e secondary clarifiers. Six secondary clarifiers have a diameter of 105-feet each . The two original c l arifiers have a side water depth of 1 2 feet and m i xed liquor fr o m the bioselector s enters the original clarifiers alon g the outside edge. Mixed liquor to secondar y clarif iers 3 and 5 flows into pipes that deliver i t to the center well of the clarifiers. T h e two newest clarifi e rs, 4 and 6, constr ucted in 1998, are also center-fed, wit h an energy
dissipating inlet and flocculation feedwell; their side water depths are 17-feet. In the secondary clarifiers, the m i xed liquor or activated solids, (also referred to as biom ass) i s settled in a quiescent environm ent. The biom ass t h at settles is drawn off the bottom and beco m es r e turn activated sludge (RAS). This m a ss is returned to the head end of the bi oselectors. A fraction of the RAS is continuously re m oved to maintain the balance betw ee n the new organic material applied each day and the total mass of organism s c ontained within the secondary s y stem

. The material re m oved is referred to as waste activat ed sludge (WAS). The WAS is rout ed to thickening processes, then conve y e d to t h e anaerobic digesters. After it passes over weirs at the outsi de edge of t h e secondary clarifiers, treat ed wastewater enters a channel and m oves to final disinfection.
Co m b ined effluent from the secondary c l arifiers is sp lit between two ultravi o let ( UV) light cham b e rs each with 4 UV channels and 2 banks of UV lights per channel. The fir s t bank of li ghts is used for disinfection with the second bank used as a backup in case of fai l ure or for maintenance. UV dosage i s set by the operator and is paced wi th the com b i n ed total primary effluent flow entering the aeration basins in service.
Disinfected effluent is disc harged thro u gh two 42-i n ch pipes which connect into a 60-inch out fall line and diffuser that extends 780 feet offshore into t h e Gord on Po int zo n e of Sout h P uget Sou n d t o a depth of approxim a tely 11 0-feet below mean lower low water. The n o minal capacity of the efflue nt pi peline is 100 MGD an d the capacity of the o u tfall is 100 MGD.

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

I NDUSTRIAL D ISCHAR GES Only fi ve industries qualify as m a jor users requiring an industrial discharge per m it for industr ial process waste w ate r in the Cha m ber s Creek Regi onal WWTP service ar ea: Boeing Corporation, Skin and Spar fabrication faci lity in Frederickson. The skins and spar facility is a metal finishing categorical user. The Boeing facility performs a boric acid anodizing process on alum inu m airpl a ne parts, along with cleaning and inspection. The m a in discharge from the facility is neutralized aci dic an d caustic rinse water. In 1998, Boein g was authorized to operate a metals pr ecipitation facility , used to red u ce water co nsum ption without exceeding categorical metals li m its. Land Recovery Incorporated (LRI) Hidden Valle y Landfill, discharges treat ed leachate fro m a lined landfill cell that recei ved m unicipal solid waste.
James Hardie Building Products, manufacture of cement-based b u ilding mater i al, principally a wallboard product made from cement and paper fiber. Pretreatment includes reduction of chrom i u m and paint soli ds. Frederickson Power operates a co m bustion tur b ine ge nerator. It does not discharge a categorical wastestream, but is perm itted as a m i nor industr y for i t s water treatment sy stem discharge, which includes a pH neutralization facility

. The Cham bers Creek Reg i onal Wastewater Treat ment Facility i s a Class IV facility and is staffed 24 hours a da y by a class IV o p erator. The facility h as ten operators which ope rate on 12-hour shifts.

D ISCHAR GE O UTFALL Effluent is discharged to Puget Soun d throug h two 4 2 -inch diam eter pipes for approxim a tely 1 , 30 0 feet. The two 42-inch lines then connect to a 60-inch dia m eter pipe that extends approximately 75 0 feet offshore ly i n g in an East to West line to a depth of approxim a tely 110 feet at mean lower lo w water. The Outfall pipe is a 60-inch dia m et er rei n forced concre te pre- stres sed pipe wit h a diffuser that has a n effective length (first to las t port) of 112 feet. The di f f user consists of eight r i sers with equal 16-foot on
center spacin g . Risers are staggered, have an inside diam eter of 44 inches, and contain a sin g le 11.9-i n ch horizontal di scharge port. An underwater inspec tio n was performed on the outfall in M a y 2 000, b y Underwater Atm o spheric Sy stem s and was found to be in good condition.

R ESIDUAL S OLID S
The treat ment facilities rem ove solids during t h e treat m e nt of the wast ewat er at the headworks (grit and screenings), and at the pri m ary and secondar y clarifi e rs , in additi on to inciden t al solids (rags, scu m , and other debris) rem oved as part of the routine m a in tenance of the equipm ent. Grit, rags, scu m an d screenings are drained and disposed of a s solid waste at the local landfill.
Wastewater solids extracted from pri m ary sedim enta t i on and th e activated sludge process ar e thickened by gravity belt thickeners, stabilized by anaerobic sludge digestion, and dewater e d by belt filt er presses. Dew a tered solids fro m the belt pres s ar e pu m p ed to the truck loading station. The biosolids are loaded onto tr ucks and transporte d to farm lan d application sites in Lewis Count y and to reclamation sites i n Cowlitz Cou n ty . Occasio n ally pri v ate co m p anies co m pos t surplus biosolids. In the future b i osolids wil l be used as p a rt of the res t oration of th e adjoinin g g r avel pits as part of t h e Cham bers Creek Properties Master Site P l an.

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

PERMIT STATUS The previous per m it for this facility was issued on Ma rch 28, 1990. The previous perm it p l aced effluent lim itations on Carbonaceous Bioc hem i cal Oxygen Demand (CBOD), To tal Suspended Solids (TSS), pH, and Fecal Coliform ba cteri a

. An application for perm it r e newal was subm itted to the Depart ment on Septem ber 23, 1999, and accepted b y the Department on Nov e m b er 14, 20 00.

SUMMARY OF COMPLIANCE WITH THE PREVIOUS PERMIT During the history of the previous per m i t , the Per m itt ee has re main ed in co m p lia nce, based on Discharge Monitoring R e ports (DMRs) subm itt ed to the Departme nt and inspections cond uc ted b y the Department.

WASTEWAT ER CHARACTERIZATION
The concentration of pollutants in the discharge wa s reported in th e NPDES application and in discharg e m onitoring reports. The effluent is characteriz ed as f o llows: Table 1: Wa stewater Effluent Characteriz a tion Parameter Concentration or Rate Flow 13.85 MGD ADWF (1) – 1 9 .83 MGD AFMM (2) CBOD 5 5.5 m g /L annual average – 10.4 m g /L maxim u m m o n t hl y average TSS 7.1 m g /L annual average – 14.9 m g /L maxim u m m o n t hl y average Fecal Coliform Bact eria 64 CFU maxim u m m onth average pH 6 SU – 7. 8 S U Te m p erature (Summer) 18 ° C avg., 20.5 ° C m a x m o nth avg. , 15 .4 ° C m i n. m onth avg. Total Amm o nia as N 19 m g /L annual average – 30 m g /L m a x i m u m m onthly average Dissolved Oxygen 5.25 m g /L annual average (1) ADWF = Average Dry Weather Flow (2) AFMM = Average Flow for Maximum Month

SEPA COMP LIANCE In accordance with WAC 197-11-855(1), perm it renewals by the Depart ment with lim its no less stringent than applicable state and federal standards are ex empt from the S t ate Environmental Policy Act (SEPA) process. This facility falls under this categor y

. PROP OSED PERMIT LIMITATIONS Federal and state regulations require that effluent limitations set forth in a NPDES perm it must be either technology

- or water quality

- b ased. T echnology

- basedli m itations for m unicipal discharges are set by regulation [ 40 Code of Federa l Regulations (CFR) 133, and C h apters 173-220 and 1 7 3

- 221 WAC]

. Water quality

- b ased lim it ations are based upon com p lia n ce wit h the Surface Water Quality Standards (Chapter 173-201A WAC), Ground Water Standards (Chapter 173-2 00 WAC), Sediment Quality Standards (Chapter 173-2 04 WAC) or the National T oxics Rule (Federal Register, Volu me 57, No. 246, Tuesday , Dec e m ber 22, 1992.) The m o st stringent of th ese ty pes of lim its m u st be chosen for each of the para m e t e rs of concern. Each of these types of lim its i s described in m o r e detail below.
The lim its in this perm it are based in part on infor m ation recei ved in the application. The effluent constituents in the applica tion were evaluated on a technology- and water quality - basis. The lim its
necess ary to meet the rule s and regulations of the st ate of Washington were deter m ined and included in

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility
this perm it. The Department does not develop effluent lim its for a ll pollutants that may be reported on the application as present i n the effluent

. Some pollutants are not treatable at th e concentrati ons reported, are not controllable at the source, ar e not listed in regulation, an d do not hav e a reasonable potential to cause a water quality vi olation

. Effluent lim its are n o t alway s developed for pollutants that may be i n th e discharge but not reported as present in the appli cation. In those circu m sta n ces the permit does not authorize discharge of the non-rep o rted pollu tants. Effluent discharge conditi ons m a y change from the conditions reported in the per m it appli cation. If significant changes o ccur in any constituent, as described in 40 CFR 122.42(a), the Perm ittee is required to notif y the Departm e nt. The Perm ittee may be in violation of t h e perm it until the perm it i s m odified to reflect additional discharge of poll u tants.

DESIGN CRITERIA
In accordance with WAC 173-220-150 (1)(g), flows or waste load ings shall not exceed appr oved design criteria. The design criteria for this treat ment facility are ta ken from the Cham bers Creek Wastewater Treat ment Plant Re-Rating and Optimization Rep o rt, October 1999 , prepared by Brown and Caldwell and are as follows: Table 2: Des i gn Standar d s for Chambers C reek WWTP.

Paramete r D e s i g n Quan t i t y Maxim u m month fl ow 28.7 MGD BOD 5 influen t concentration 242 m g /L BOD 5 influen t loading 57,9 25 lbs/da y TSS influent concentration 303 m g /L TSS influent loading 72,525 lbs/da y
TECHNOL OGY-BASED EFFLUENT LIMITATIONS Municipal w astewater treat m ent plants are a categor y of discharger for which technology

- based effluen t lim it s have b een pro m ulgated by federal and state reg u lations. These effluent li mitations are given in the Code of Fed e ral Regulations (CFR) 4 0 CFR Part 133 (federal) and in Chap ter 173-2 21 WAC (state). These regulations are performance stan dards that cons titute all known available and reasonable m e thods of prevention, control, and treat ment for m unicipal w a stewat er. The following technology-based li m i t s for pH, f ecal colifor m , BOD 5 , and TSS are taken from Chapter 173-2 21 WA C are: Table 3: Technology-b a sed Lim i ts.

P a r a m e t e r L i m i t pH: shall be within the range of 6 to 9 standard units. Fecal Coliform Bact eria Monthl y Geometric Mean = 200 or ganisms/100 m L Weekly Geo m etric Mean = 400 or ganisms/100 m L CBOD 5 (concentration) Average Monthl y Lim it is the m o st stringent of the fo llowing: - 25 m g /L - may not exceed fifteen percent (15%) of the average influent conc entration Average Wee k ly Lim it = 40 m g /L

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

P a r a m e t e r L i m i t TSS (concentration) Average Monthl y Lim it is the m o st stringent of the fo llowing: - 30 m g /L - may not exceed fifteen percent (15%) of the average influent conc entration Average Wee k ly Lim it = 45 m g /L Total Residual Chlorine (concentration) Average Monthl y Lim it = 0.5 m g /L Average Wee k ly Lim it = 0.75 m g /L The following technol ogy-based m a ss lim its ar e based on WAC 173-220-130(3)(b) a nd 173-221- 030(1 1 )(b).
CBOD 5 m o n t hl y effluent m a ss loadings (lbs/d ay ) were calculat e d as the maxi m u m m o n t hly design flow (28.7 MGD) x Concentration lim i t ( 2 5 mg/L) x 8.3 4 (conversion factor) = m a ss limit 5,98 4 lbs/da y

. CBOD 5 week ly effluent mass loadings (lbs/day ) we re calculated as the m a xi m u m monthly design flow (28. 7 M GD) x Concentration lim i t ( 4 0 m g /L) x 8.34 (conversion factor) = mass lim i t 9 , 5 7 4 lbs/day

. TSS m onthly effluent mass loadings (lbs/day ) were calculated as t h e maxi m u m m onthly design flow (28. 7 M GD) x Concentration lim i t ( 3 0 m g /L) x 8.34 (conversion factor) = mass lim i t 7 , 1 8 1 lbs/day

. TSS weekly effluent mass loadings (l bs/day ) were calculated as the m a xi m u m monthl y design flow (28.7 MGD) x Concentration lim it ( 4 5 m g /L) x 8.34 (convers ion factor) = m a s s l i m i t 1 0 , 7 7 1 lbs/day

. SURFACE WATER QUALITY-BASED EFFLUENT LIMITATIONS In order to protect existing water quality and preser ve the designated beneficial uses of Washington's surface water s , WAC 173- 201A-060 states that waste disch arge per m its shall be conditi oned such that the discharge wil l m eet est ablished Surface Water Qualit y Standards. The Washington State Surface W a te r Quality Standards (Chapter 173-201A WAC) is a state regulation designed to protect the beneficial uses of the surface waters of the state. Water quality

- based effluent lim itations m a y be based on a n individual waste load allocation (WL A ) or on a W L A developed duri ng a ba sin-wide total maxim u m d a ily l o ading study (TMDL).

N UMERICAL C RITERIA F O R THE P ROTECTION OF A Q UATIC L IFE "Numerical" water quality criteria are num eri cal values set forth in the state of Washingt on' s Wate r Quality Standards for Sur f ace W a ters ( C hapter 173- 201A WAC). They specif y t h e levels of pollutants allowed in a receiving wate r while re maining protective of aquatic life. Nu m e ri cal criteri a se t forth in the Water Qualit y Standards are used along with chem ical and phy s ical data for the wastewater and receiving water to deri ve the effluent li m its in t h e discharge perm it. When surface wat e r quality -bas ed li m its are
m o r e stringent or potenti ally m o re str i ngent than t echnology

- based li m itatio ns, they m u st be used in a perm it.

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

N UMERICAL C RITERIA F O R THE P ROTECTION OF H U M AN H EALTH
The state was issued 91 numeric w a ter quality criteria for th e prote c tion of hum an health b y th e U.S. EPA (EPA 1992). These criteria are designed to prote c t hum ans fr om cancer and other dis ease and ar e primarily applicable to fish and shellfish cons um ption and drinking water fro m su rface w a ters.

N ARRATIVE C RITERIA
In addition t o num erical criteria, "narrative" water quality criteria (WAC 173-201A-030) lim it toxic, radioactive, or deleterious m a terial concentrations below those which have the potential to adversely affect chara c t eristic water uses, caus e acute or ch ronic toxicity to biota, im p a ir a esthe tic values, o r adversely affect hu m a n he alth. Narrati ve criteria pr otect the specific benefici al uses of all fresh (WAC 173-2 01A-13 0 ) and m a rine (WAC 173-2 01A-140) wat e rs in the State of Washing t on.
A NTIDEGRAD A TION
The state of Washington' s Antidegradation Polic y re quir es that discharges into a rec e iving water shall not further degrade the existing water quali ty of the wate r body

. In cases wh ere t h e natural co nditions of a receiving wat e r ar e of lower quality tha n the criteri a assigned, the natural conditions shall co nstitute the water quality criteria. Similarly , whe n the natural conditions of a receiving water ar e of higher quality than the crit eria assigned, the natural conditions shall constit ute the water quality crit eria. More inform ation on the state Antidegradation Policy can be obtained b y r e ferring to W A C 173-201 A-070. The Depart ment has reviewed existing records and is unable to determ ine if am bient wat e r qualit y is either higher or lower than the designated classi fi cation criteria given in Chapter 173- 201A WAC; therefore, the Department will use the designated clas sification criteria for this water body in th e proposed per m it. The discharges au thorized by th is proposed per m it should not cause a loss of beneficial uses.

C RITICAL C ONDITIONS
Surface water qualit y - based lim its are d e rived for the waterbody ' s critical condition, which re presents the receiving wat e r and waste discharge condition with the highest pote n tial for adve rse i m pact on the aquatic biota, hum an health, and existing or characteristi c wat e r body uses.
M IXING Z ON ES The Water Quality Standa rds allow the Department to authorize m i xing zones around a po int of d i scharge in establishing surface wat e r quality -based effluent limits . Both "acute" and "chronic" m i xing zones m a y be authorized for pollutant s that can have a toxic effect on the aquatic enviro nment near the point of discharge. T h e concentrat ion of pollut a nts at the b oundar y of th ese mixing zones may not exceed the
num eri cal cri t eria for that ty pe of zone. Mixing zones can only be authorized for discha r ges that ar e receiving all known, avail a ble, and reasonable methods of prevention, control and treatment (AKART) and in accordance with other m i xing zo ne requirem e nt s of WAC 173-201A-100.
The National Toxics Rule (EPA, 1992) allows the chroni c m i xing zone to be used to m e et human health criteria.

D ES CRIP T ION OF THE R ECEIVING W ATER The facility discharges to Puget Sound Gordon Point Area which is designated as a Class AA (extraordinary ) receiving water in the vicinity of th e outfall under WAC 173-201A-140(21).

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Characteri s tic uses include the following: water supply (dom estic, i ndustrial, agr i cultural); stock watering; fish m i gration; fish and shellfish r earing, spawning and harvesting ; wildlife habitat; primary contact re creatio n; sport fishing; boating and aesthet i c enjoy m ent; co mmerce and navigation. Water quality of this class shall m a rkedl y and unifor mly exceed the requirements for all or substantially all uses.

S URFACE W ATER Q UALITY C RITERIA Applicable criteria are defined in Chapt e r 173-201A WA C for aquatic biota. I n addition, U. S. EPA has prom ulgated hum an health criteria for t oxic pollutant s (EPA 1992). Criteria fo r this receivi ng water are
su mmarized below:

Fecal Coliforms Fecal coliform organis m levels shall both not exceed a geometric mean value of 1 4 colonies/10 0 m L , and not have
m o re than 10 percent of all sam p les obtained for calculating the geometric mean value e x ceeding 43 colonies/100 mL. Dissolved Oxygen Dissolved oxygen shall exceed 7.0 m g / L

. Te m p erature Te m p erature shall not exceed 13.0 o C due to h u m an activities. When natural conditions exceed 13.0 o C, no tem p erature i n creases will be allowed which will raise the receiving wat e r te m p er ature by greater than 0.3 o C. pH pH shall be within the rang e 7.0 to 8.5 w ith a hum ancaused variati on within a ra nge of less than 0.2 units. Turbidity Turbidity shall not exceed 5 NTU over background turbidit y when the background t u rbidit y is 50 NTU or less, or have m o re than a 10 percent increas e in turbidity w h en the backgrou nd tur b idity i s m o re than 50 NTU. Toxics Toxic, radioa ctive, or dele terious materi al concentrations shall be below those which have the potential either singularl y or cu m u latively to adversely a ffect characteristic water use s , ca use acute or c h ronic conditions to the m o st sensitive biota dependent upon those waters, or adversely affect public health, as deter m ined by the depart m e nt (see WAC 173-20 1A-040 and 1 73-20 1A-050 ).

C ONSI D ERATION OF S URFA CE W ATER Q UALITY -B AS ED L IMITS FOR N UMERIC C RITERIA Pollutant concentrations in the proposed dischar ge exceed wat e r quality criteria with technology -based controls which the Department has dete r m ined to be AKART. A mixing zone is authorized in accordance with the geo m etric configuration, flow restriction, and other restrictions for m i xing zones in C h apter 173- 201A WAC and are defined as follows:
The dilution factors of effl uent to receiving water th at occur within these zones w e re deter m ine d at the critical condition d u ring th e outfall evaluation for t h e Cha m bers Cr eek Waste w at er Treat ment Plant Optim i zation Stud y , Octob e r 1999, prep ared by Brow n and Caldwell, using t h e P L UMES m odel. The dilution factors have been deter m ined to be (from Ap pendix C):

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A c u t e C h r o n i c Aquatic Life 16.7 168
Pollutants in an effluent may affect the aquatic environm ent near the point of discharge (nearfield) or at a considerable distance fro m the point of discharge (far fi eld). Toxic pollutants, for exam ple, ar e near-fi eld pollutants--their adverse effects di m i nish rapidl y w ith m i xing i n the receiving water. C onversely , a pollutant suc h as BOD is a far-field pollutant whose a dverse effect occurs away from the discharge even after dilution has occurred. Thus, the m e thod of ca lculating water quality -ba sed effluent lim its varies with the poi nt at which the pollutant has its m a xi m u m effect. The derivation of water qualit y - based lim it s also ta kes into account the va riability of th e pollutant concentrations in both the effluent and the receiving water.
The critical conditi on for the Cham bers Creek WWTF discharge located in the Gordon Point zone i n South P uget Sound used f o r this perm it includes the f o l l o w i n g :

Ambient Par a mete r Value used
Tem p erature (m in.) Summer 10.54 o C – Winter 8.45 o C pH 7.99 SU – 7. 5 4 SU Dissolved Oxygen (m in.) Summer 6.09 m g /L – Winter 7.90 m g /L Salinit y (avg. ) Summer 28.98 ppt – Winte r 28.2 3 pp t
BOD 5 --This discharge wi th technology

- based li m i t a ti ons results in a small am ount of BOD loading relative to the large amount of dil u tion occurring in th e receiving water at critical conditions. Technology

- based li m itati ons will be pr otective of di ssolved oxygen criteria in the receiving water.
Te m p erature

- - The im pa ct of the discharge on the te m p erature of the receiving water was m odel e d by si m p le mixing analy s is at critical condit i on and a chronic dilution factor of 168:1. The average receiving water temperature at the critical condition is 12.13 o C during October and the average effluent te m p erature is 18.85 o C. The predicted resultant tem p erature at the boun dar y of the chron i c m i xing zone is 12.17 o C and the incremental rise i s 0.04 o C.
Under critical conditions there is no predicted viol ation of the Water Quality Standards for Surface Waters. Therefore, no effluent lim itatio n for te m p era t ure was plac ed in the proposed per m it. pH --Because of the high buffering capacity of m a rin e wa t e r, co mpliance with t h e technology

- based li m i t s of 6 to 9 will assure co m p li ance with the Water Qualit y Standards for Surface Waters.
Fecal coliform --The concentration of fecal colifor m organi s m s a t the edge of allowable mixing zones
were m odel e d by sim p le mixing anal ysis using th e technology based li m it of 400 colonies per 100 m L , a chronic diluti on factor of 168:1 , and an am bient con centration of 3 colonies per 100 m L . This y i elds a concentration at the edge o f the chronic mixing zone of 5.3 6 colo ni es per100 m L

. Under critical conditions there is no predicted viol ation of the Water Quality Standards for Surface Waters with the technology

- b ased lim it . Therefore, the technol ogy -based effluent lim itation for fecal coliform bact eria wa s plac ed in the proposed per m it.

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Toxic Polluta nts --Federal regulations (40 CFR 122.4 4 ) require NPDES perm its to contain effluent lim it s for toxic che m ical s in an effluentwhenever there is a reasonable pot ential for those chem i cals to excee d the surface water quality c r iteria. This process occu rs concurrently with the derivation of t echnology

based effluent li m its. F acilities with technology

- b ased effluent li m its def i ned in regulation are not
exe m pted fro m meeting th e Wat e r Qual ity Standards for Surface Waters or fro m having sur f ace wat e r quality

- based effluent lim it s. The following toxics were deter m ined t o be present in the discharge: chlorine, amm onia, copper, lead, seleniu m , and zinc. A reasonable potent i al analy s is (See Appendix C) was conducted on the se parameters to determ ine whether or no t effluent lim it ations would be required i n this perm it.
The determ in ation of the reasonable potential for chlori ne, amm o nia, copper, lead, seleniu m, and zinc to exceed the water quality criteria was evaluated with procedures gi ven in EPA, 1991 (Appendix C). The para m e t e rs us ed in the m odeling are as follows: an a c ute dilution factor of 16.7 : 1, and a chronic diluti on factor of 168: 1

. At the prese nt tim e the Cha m bers Cr eek WWTF is switching from chlorine to ultraviol e t light for disinfection and will have chlorine as a backup for one y ear as a safe guard. It is not anticipated that any chlorine use will exceed the water quality criteria based on past residual concentrations and the contact time provide d in the final tank an d add itional contac t tim e in the length of the discharge pip e , therefore, no lim it on chlorine was placed in the proposed permit.
The deter m in ation of the reasonable potential for total ammonia as NH3-N to exceed the water quality criteria was evaluated with procedures g i ven in EPA , 1991 (Appendix C) at the critical con d ition. The critical condition in this c ase occurs during August and Septem ber. The parameter s used i n the critical condition m o deling are as follows: acute dilution factor 16.7, chronic dilution f actor 168, receiving water te m p erature 13.97 o C, receiving water pH 7.9 SU, receiving water salinity 27.94 ppt, receiving wate r NH43D concentration 0. 0 285 m g /L 99 th percentile and 0.026 m g /L 95 th percentile. Under these critical conditions there was no predicted vi olation of the Surface Wat e r Quality Standards for total amm onia as NH3-N, there f ore no lim it on total ammonia as NH3- N wa s placed in the proposed per m it. The effluent will be subject to a bio m onitoring program for t oxics, and if amm onia is found to be a problem , corrective act ion will be re quired.
The deter m i n ation of the reasonable potential fo r copper to exceed the water quality criteria was evaluated with procedure s given in E P A, 199 1 (A ppendix C). The parame ters used in the critical condition m o deling are as follows: acute dilution factor 16.7, chronic dilution f actor 168, hi ghest effluent total copper concentration 22 μ g /L, effluent copper co efficient of variation 0.3 596, and the num ber of effluent copp er sam p les was 15. Alth ough there is no valid ambient data for copper in th e immediate area around the Cham bers Creek WWTF outfall, n earby comm encem e nt bay copper values range fro m 0.24μ g/L t o 0.66 μ g /L. Using the commen c ement ba y values th ere was no predicted vio l ation of th e Surface Wat e r Quality Standards for copper. In or der for there to be a r e asonable potential for the Cham bers Creek WWTF effluent to v i olate the wa ter quality sta ndards for co pper the am b i ent copper concentrations would have to exceed 1.98 μg/L. Since it is hi ghl y unli k el y for th e am b i ent copper concentrations in the area of the Cham b e rs Creek outfall to greatly exceed those found in commen c e m ent bay no lim it on copper was placed in the proposed pe r m it. The highest effluent value for lead was 2 μg/L which is below the marine waters water quality standard of 199 μg/L acute and 7.7 μg/L chronic. Since the Cham b e rs Creek effluent m eets the marine water quality standard for l ead at the end of pipe no li mit on lead was placed in the proposed per m it. The highest effluent value for selenium was 2 μg/ L which is below the marine waters water quality standard of 289 μ g /L acute and 71 μ g /L chronic. Since the Cham b e rs Creek effluent m e ets the marin e

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

water quality standard for seleniu m in th e effluent, pri o r to m i xing, no lim it on selenium was p l aced in the proposed per m it. The highest effluent value for zinc was 56 μ g /L whic h is below the m a rine waters water quality standard of 85 .14 μ g /L acute and 76.2 μ g /L ch ronic. Si nce the Cham b e r s Creek effluent meets the marine wate r quality standard for zinc i n the effluent, prior to m i xing, no lim i t on zinc was placed in t h e proposed perm it. Water quality criteria for metal s in Chapter 173-201 A WAC are based on the dissolved fr action of th e metal. The Perm ittee may provide data cl early dem onstrating the seasonal partitioning of the dissolved metal in the am bi ent wat e r in relation to an effluent discharge. M e t a ls crit eria may be adjusted on a sitespecific basis when data is available clearly dem onstr ating the seasonal partitioning in the ambient water in relation to an effluent di scharge.

W HOLE E FFLUENT T OXICITY The Water Quality Standa rds for Surfa ce Waters r e quire that the effluent not cause toxic effects in the receiving wat e rs. M a ny toxic pollutants cannot be de tected by commonly available detectio n m e thods. However, toxicity can be measured directly b y expo sing living or ganism s to th e wastewater in laborator y tests and m e a s uring the response of the organisms. T oxicity tests measur e the aggregate toxicity of the whole effluent, and th erefore this appr oach is called whole effluent toxicity ( W ET) testing. Som e WET tests measur e acute toxicity and other WET tests measure chronic toxicity

. Acute toxicity tests m e asure m o rtality as the signifi cant response to the t oxicity of th e effluent. Discharger s who m onitor their waste w ater with a c ute toxicit y tests are providing an in dication of t h e potential lethal effect of the effluent to organis m s in the receiving environm ent.
Chronic toxi city tests m e asure various sublethal to xic responses such as reta rded growth or reduced reproduction. Chronic tox i city tests often involve eith er a co m p lete life cy cle test of an organism with an extre m ely short life c y cle or a partial life cy cle test on a critical stage of one of a test organis m 's life cy cles. Organis m survival is also m e a s ured in som e c h ronic toxicity tests. Accredited WET testing laboratories have the proper WET testing protoco l s, data requirem e nts, and reporting for m at. Accredited laboratories are know ledgeable about WE T testing and capable of calculating an NOEC, LC 50 , E C 50 , IC 25, etc. All accr edited labs have been provided the m o st recen t version of the Department of Ec olog y Publication # WQ-R-95-80, Labora t o ry Guidance and W hole Effluent Toxi city Test R e view Criteria which is referenced in the perm it. Any Perm ittee i n terested i n receiving a copy of this publication m a y call the De part m e nt Publications Distribution Cent er 360-407- 7472 f o r a copy . The D e partm e nt reco mmends that Perm ittees send a copy of the acute or chronic toxicity sections(s) of thei r perm its to their laboratory of choice. Acute toxicity was m e asur e d during effluent characte r i zation in th e previous pe rm it term . Acute toxicit y was found to be at levels that, in accordance with WAC 173-205-050(2)(a), have a reasonabl e potential to cause receiving water toxi city . An acute toxicit y l i mit is therefore required. The acute toxicity lim it is no statistically significant difference in test organi sm survival between th e acute crit ical effluent concentration (ACEC), 5.9 percent of th e effluent, and the control

. The acute toxicity lim it is set relative to the zone of acute criteria exce eda n ce (acute mixing zone) established in accordance with WAC 173-201A-100. The acu te critical effluent concentration (ACEC) is the concentration of efflue nt existing at the boundar y of the acute mixing zone during critical conditions.
Monitorin g f o r com p liance with an acute toxicit y li mit is acco mplished b y co nducting an acute toxicit y test using a sam p le of effluent diluted t o equal th e ACEC and c o m p aring test organism su rvival in the

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

ACEC to survival in nont oxic control water. The Perm ittee is in co m p liance with the acute toxicity limit if there is no statistically significant di fference in test organis m survival between the AC EC and the control.
Chronic toxic ity was measured in the pr evious perm it term . This toxicit y was f ound t o be at levels that, in accordance with WAC 173-205-050(2)(a), have a reasonable potential to cause receiving water toxicit y . Th e results of this WET testing cannot b e used to characterize effluent toxicit y or make th e regulator y deter m ination required in Chapter 173-205 WAC. In accordance with WAC 173-205- 030(5)( b ), the Perm ittee is required to conduct a efflue nt characterization for whole effluent toxicit y

. H UMA N H EALTH Washington ’s water quality standards now includ e 91 num eri c health-base d criteria that m u st be considered in NPDES per m its. Thes e criteria wer e pro m ulgated for the state by the U.S

. EPA in its National Toxi cs Rule (Federal Register, Volume 57, No. 246, Tue s day , December 22, 1 992)

. The Depart ment has deter m ined that the applicant' s discharge does not contain che m ic al s of concern based on existing data or knowledge. The discharge w ill be re-ev a luated for im p acts to human health at the next permit reissuance.

S EDIMENT Q UALITY The Department has promulgated a quatic sediment standards (Chapter 173-20 4 WAC) to protect aquatic biota and human health. These standar d s state that t h e Depart ment m a y require Per m ittees t o evaluate the potential for th e discharge to cause a violation of appli cable standards (WAC 173 -204-4 00). The Department has determ ined through a revi ew of the discharger characteristics and effluen t characte r istic s that this discharge has no reasonabl e potential to violate the Sedim e nt Management Standards. GROUND WATER QUALITY LIMITATIONS
This Per m ittee has no discharge to ground and theref ore no lim it ations are req u ired based on potential effects to ground water.

COMPARIS O N OF EFF LUENT LIMITS WITH THE EXISTING PERMIT ISSUED March 28, 1990.

Existing Limits Proposed Limits
CBOD 5 25 m g /L 3,7 50 lbs/da y 40 m g /L 6,0 05 lbs/da y CBOD 5 25 m g /L 5,9 84 lbs/da y 40 m g /L 9,5 74 lbs/da y TSS 30 m g /L 4,500 lbs/da y 45 m g /L 6,7 60 lbs/da y TSS 30 m g /L 7,181 lbs/da y 45 m g /L 10, 771 l b s/da y F. Coliform 200/10 0 m L - 400/1 00 m L F. Coliform 200/10 0 m L - 400/1 00 m L pH 6.0 - 9.0 pH 6.0 - 9.0 No acute toxicity detected in a test concentration representing the acute criti cal effluent concentration (ACEC). No chronic toxicity detected in a test

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility
concentration representing the chronic critical effluent concentration (CCEC). If any of the tests conducted for effluent characterization shows a significant differe nce between t h e control and th e ACEC.

MONI TORI NG RE QU I R EMEN TS

Monitorin g , recording, and reporting are required (WAC 173-220- 210 and 40 CFR 122.41) t o verify that the treat m e nt process is functioning corre ctly an d the e ffluent lim itat i ons are being achieved.
Reduced m o nitoring frequencies ar e allowed for de m onstr ated good perform ance and are based on the ratio of the long term effluent average to the average m onthly lim it. The perm it writer’s manual
reco mmends that for an ac tivated sludge plant with a flow great e r than 5 MGD that CB O D 5 and TSS be
m onitored at least 5/we ek and Fecal Coliforms be mon itored on a daily basis. The ratio of the LTA to AML of the Cham bers Creek Effluent for the following paramet e rs is: CBOD 5 – 42 percent; TSS – 46 percent; and Fecal Coliforms – 32 percent. Based on these ratios of LTA to AML the permit write r s manual then allows a reduction for CBOD 5 and TSS from 5/ week down to 2/week and for Fecal Coliforms from 7/w eek down to 3/week per Table XIII-1A1. These reductions in m onitoring frequencies will be incorporated into the proposed pe rm it. Monitoring of sludge qua ntity and qua lity is necessary to determine the appropriate uses of the sludge. Sludge m onitoring is requi red b y the current state an d local solid waste management program and also by EPA under 4 0 CFR 503.
The m onitori ng schedule is detailed in the proposed perm it under Condition S.2. Specified m onitoring frequencies take into account the quantity and va ri ability of discharge, the treatm e nt method, past
co m p liance, significance of pollutants, and cost of m onitoring. The required m onitoring frequency i s consistent with agenc y g u i d ance given i n the current version of t h e Departm e nt’s Permit Writer's M anual (July 1994) f o r activated sludge secondary treatment. As a pretreatment POTW, Pierce County is required to have infl u e nt, final effluent, and slu dge sam p led for toxic p o ll utants in or d e r to characterize the indus trial input. Sam p ling is also done to determ ine if pollutants i n t e rfere with the treat m e nt process or p ass through the plant to the sludge or t h e receiving water. The m onitoring data will be used by Pier ce County to de velop local limits which commercial and industrial users m u st meet.

LAB ACCREDITATION With the exception of certain para meters the permit requires all m on itoring data to be prepared by a laborator y re gistered or a ccredited under the pr ov isions of Ch apter 173-5 0 WAC, Accreditation of Environmental Laborator i es. The laboratory at the Cha m bers Creek WWTF is accred ited for the following par a m e t e rs: Alk a linity , Ammonia, Bioc hemical Oxy g e n Demand, Carbonaceous Biochem i cal Oxygen Demand, Chem ical Oxy g en D e m a nd, Chlorine Residual, Dissolved Oxy g en, Hardness, Nitr ate, Nitrate + Nitrite, Nitrite, Total Kjeldahl Nitrogen, Oil & Grease, Orthophosp h ate, pH, Total Persulfate Phosphor us, Salinit y , Tota l Dissolved Solids, Total Suspended Solids, Total Volatile Solids, and Fecal Coliforms.

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

OTHER PE RMIT C O N D ITI O NS

REPORTING AND RECORDKEEPING

The conditions of S3 are based on the authority to specify any appropriate reporting and re cordkeeping requirem e nts to prevent an d control waste discharges (WAC 173-2 20-21 0).

PREVENTION OF FACIL ITY OVERLOADING Overloading of the treatment plant is a violatio n of the terms and conditi ons o f the perm it. To prevent this from occurring, RCW 90. 48.110 a nd WAC 173-220- 150 require the Per m ittee to take the actions detailed in proposed perm it requirem e nt S.4 to plan e xpansions or m odifications before existi ng capacity is reached and t o report and correct conditi ons t h at could result in new or increased discharges of pollutants. C onditi on S. 4 r estricts the am ount of flow.

OPERATION AND MAINT E

NANCE (O&M) The proposed perm it contains Condition S.5 as au thorized under RCW 90.48. 110, WAC 173-220-150, Chapter 173-230 WAC, and WAC 173 -240-0 80. It is included to ensure proper operation and regular maintenance of equipm ent , and to ensur e that adequa te safeguards are taken so that constructed facilities are used to their optim u m potential in te rm s of pollut a nt capture and treatment.

RESIDUAL SOLIDS HANDLING To prevent water quality problems the Perm ittee is requi red in permit Condition S7 to store and handle all residual solids (grit, screenings, scu m , sl udge, and othe r solid wast e) in accordan ce with the r e quirements of RCW 90.4 8 .08 0 and Sta t e Water Qualit y Standards

. The final use and disposal of sewage sludge from this facility is regulated by U.S. EPA under 40 CFR 503. The dis posal of other solid waste is under the ju risdiction of t h e Pierce Co unty Health Department. Requirem e nts for m onitoring sewage sludge and r ecordkeeping are included in t h is pe rm it. This inform ation will by used by the Department to devel op or update l o cal lim its an d is also requi red under 40 CFR 503.

PRETREATMENT To provi de more direct and effective co ntrol of pollu tants discharged, Pierce County has been delegated perm itting, m onitoring and enforcement authority for industri a l users discharging to th eir treatment sy stem

. The Depart ment oversees the delegated I ndustrial Pretreat m e nt Progr am to assure co m p liance with federal pretreatment regulations ( 40 CFR Part 403) an d categorical standards and state regulations (Chapter 90.4 8 RCW and Chapter 173- 216 WAC).

SPILL PLAN The Depart ment has determined that the Perm itt ee stor es a quantity of chem ical s that have the potential to
cause water p o llution if accidentally released. The Depa rt ment has the authority to require the Per m itte e to develop be st m a n a gement plans to prevent this accidental release under sectio n 402(a)(1) of the Federal Water Pollution Contr o l Act (FWPCA) and RCW 90. 48.0 80.

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

EFFLUENT MIXING STUDY The Department has estimated the amo unt of m i xing of the discharge within the authorized mixing zone to deter m ine the potential for violations of the Wa ter Quality Standards for Surface W a ter s ( C hapter 173- 201A WAC). Conditi on S.8 of th is per m it requires the Per m i ttee to m o r e accurately deter m ine th e mixing characteristics of the discharge. Mixin g will be m e asured or m odeled under con d iti ons specified in the per m it to assess whether assu m p ti ons m a de about diluti on will protect t h e receiving water quality outside the allotted dilu tio n zone bo und ary

. OUTFALL EVALUATION Proposed permit Condition S.11 requir es the Perm ittee to condu ct an outfall inspection and subm it a report detailing the fi ndi ngs of t h at i n spection. The purpose of the i n spection is to determ ine the condition of the discharge pipe and diffusers and to dete rm ine if sedi m e nt is accu m ulating in the vicinity of the outfall.

GENERAL CONDITIONS
General Conditions are based directly on state and fe de ral law and regulations and have been standardiz e d for all indiv i d u al m unicipal NPDES permits issued by the Department.

PERMIT IS SUAN CE P R OC EDU R E S

PERMIT MODIFICATIONS The Depart ment m a y m odify this per m it to i m pose num eri cal li mitations, if necess ary to meet Water Quality Standards, Sediment Quality Standards, or Ground Water Standards, based on new information obtained fro m sources such as inspections, effluent m onitorin g , outfall studies, and effluent m i xing studies. The Depart ment may also m odify this per m it as a res u lt of new or am ended stat e or federal regulations.

RECOMMENDATION FOR PERMIT ISSUANCE This proposed perm it mee t s all statutory requirements for authorizing a waste w ater dischar ge, including those li m itati ons and conditions belie ved necess ar y to protect hum an he alth, aquatic life, and the beneficial use s of waters of the state of Washington. The Department proposes that this permit be issued for five y ears.

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

REFER E NC ES FOR TE X T AND AP PENDI CES

Environm ental Protection Agency (EPA )
1992

. N a t i o n a l Toxics Rule. Federal Register, V. 57, No. 246, Tue s day , December 22, 1 992

. 1 9 9 1

. T e c h n i cal Support D o cument for Water Qualit y - based Toxi cs Control . E P A/505/2-9 0

- 001.
1 9 8 8

. T e c h n i cal Guidance on Supplementary S t r eam Design Conditions for Steady State Modeling

. USEPA Office of Water, Washington, D.C.
1 9 8 5

. W a t e r Quality Assessment: A Screening Proce dure for Toxic and Conventional Poll utants in Surface and Ground Water . EPA/600/6

- 85/00 2a.
1 9 8 3

. W a t e r Q u a l i t y Standards Handbook. USEPA Office of Water, Washington, D.C. Metcalf and Eddy

. 1991

. W a s t e w a t e r E n g i n e e r i n g , T r e a t m e n t , D i s p o s a l , a n d R e u s e . Third Editi on. Tsivoglou, E.C., and J.R. Wallace.
1972

. C h a r a c t e r i z a t i o n o f S t r e a m Reaeration Capacity . EPA-R3-7 2 -012. (Cited in EPA 19 85 op.cit.) Washington State Department of Ecolog y

. 1994

. P e r m it Writer’s Manual . Publicati on Num b er 92-109
Water Pollution Contr o l Fe deration.
1976

. C h l o r i n a tion of Wastewater

. Wright, R.M. , and A.J. McDonnell.
1979

. I n
- s t r e a m Deoxy gena tion Rate Prediction . Jour n a l Environm ental Engineer ing Division , ASCE. 105(EE2). ( C ited in EPA 198 5 op .cit.)

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

APPEND IX A--PUBL I C INV O LV E M ENT I N F O RMA T I O N The Depart ment has tentatively deter m ined to reissue a perm it to the applicant listed on page 1 of this fact sheet. The p e rm it contain s conditions and effluent lim ita tions wh ich are de scri b ed in the res t of this fact sheet.
Public notice of applicatio n was published on Jul y 21, 2 002 , an d Jul y 2 6 , 2 002, i n the Tacoma News Tribune to i n form the public that an application ha d been subm itted and to invite comment on the reissuance of this perm it. The Department will publ ish a Public Notice of Draft (PNOD) on _____ _______________, in the Tacoma News Tribune to inform the public that a draft per m it a nd fact sheet are available for review. Interested persons are invited to subm it written co mme nts regarding the draft perm it. The draft perm it, fact sheet, and related documents are available for inspection and cop y ing between the hours of 8:00 a. m. and 5:00 p.m. weekday s , by appointm e nt, at the re gional office listed below. Written co mments should be mailed to: Water Qualit y Perm it Administrator Department of Ecolog y Southwest Regional Office P.O. Box 47 7 75 Oly m pia, WA 9850 4-77 7 5

. Any i n terested part y m a y co mment on the draft permit or request a public he aring on t h is draft perm it within the 30-day comm ent period t o th e address above . T h e request for a hearing shall indicate the interest of the party and the reasons why the hearing is warranted. The Depart ment will hold a hearing if it determ ines there is a sig n ificant publi c interest in the draft permit (WAC 173-220-0 90). Public notice regarding any hearing will be circulat ed at least 30 day s in advance of the hearin g. People ex pressing an interest in thi s perm it will be mailed an indivi dual notice of hearing (WAC 173- 220-100).
Co mments sh ould reference specific tex t followed b y proposed modification or concern when possible. Co mments may address technical issue s , accuracy and com p lete ness of information, the s c ope of the facility’s proposed coverage, adequacy of environm ental protection, perm it conditions, or any other concern that would result from is suance of this perm it

. The Depart ment will consider all comments received within 30 da y s from t h e date of public notice of draft indicated above, in f o rm ulating a final determin ation t o issue, revise, or den y the pe rm it. The Department's response to all significant comments is av ailable upon request and will be mailed directl y to people expressing an interest in this permit.
Further infor m ation m a y be obtained fr om the Depart m e nt by tele phone, ( 360) 407-6275, or by writing t o the address listed above. This perm it a nd fact sheet were writt en by Glenn Pieritz.

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

APPENDIX B--GLOSSARY
Acute Toxici ty --The lethal effect of a pollutant o n an organi sm that occurs within a short peri od of tim e, usually 48 to 96 h ours. AKA R T -- An acrony m for “all known, available, and reas onable m e thods of prevention, control, and treat ment”. Ambient Water Quality

-- The existing environm ental condition of the water in a receiving water body

. Ammonia --Amm onia is produced b y the breakdown of nitr o g en ous materials in wastewater. Amm onia is toxic to aq uatic organisms, exerts an ox ygen demand, and con t ributes to eu trophication. It also increases the am ount of chl o rine n eeded to disinfect wastewater. Average Monthly Discharge Lim i tation --The highest allowabl e average of daily discharges over a calendar m o nth, calculate d as the su m of all daily discharges measured duri ng a calenda r m onth divided by the num ber of daily discharges m e a s ured during that m onth (excep t in the case of fecal coliform )

. T h e daily discharge is c a lc ulated as the average measurem ent of the pollutant over the day

. Average W e ekly Dischar ge Limitatio n -- The highest allowabl e aver age of daily discharges over a calendar wee k , calculated as the su m of all daily discharges measu red during a calendar we ek divided b y the num ber of daily di scharges measured during th at week. T h e daily disc harge is cal c u lated as the average mea s ure m ent of the pollutant over the day. Best Management Pract i ces (BMPs) --Schedules of activities, prohibitions of practices, maintenanc e procedures, and other ph y s ical, structural and/or managerial practice s to p r event or re duce the pollution of waters of the State. BMPs include treatment sy ste m s , operating procedures, and practices to control: pl ant site runoff, spillage or leaks, sludge or waste disposal, or dr ainage fro m raw m a terial storage. BMPs m a y be further categorized as op erational, source control, erosion and sedi m ent control, and treat ment BMPs. BOD 5 --Det er mining the Bioche m i cal O x y g en Dem a nd of an effluent is an indirect way of measuring the quantity of organic materi al present in an effl uent that is utilized by bacteria. The BOD 5 is used in
m odeling to measur e the reduction of dissolved oxygen in a receiving water aft e r effluent is discharged. Stress caused by reduced dissolved ox ygen levels m a k es organism s less co m p etiti ve and less able to sustain their species in t h e aqua tic environm ent. Although BOD is not a specifi c co m pound, i t is defined as a conventiona l pollu tant un der the federal Clean Water Act. Bypass --The intentional di version of waste stream s from any porti on of a treatment facility

. CBOD5 – The quantit y of ox y g en ut ilized by a mi xed popul ation of m i croorganism s acting on the nutrients in the sa m p le in an aerobic oxidation for fi ve da y s at a controlled temperature of 2 0 degrees Celcius, with an inhibit o r y agent added to prev ent the oxidatio n of nitrogen com poun ds. The method for determ ining CBOD5 is given in 40 CFR Part 136

. Chlorine --C hlorine is used to disinfect waste w ate r s of pa thogens harm ful to hum an health. It is also extrem ely toxic to aquatic life. Chronic Tox i city --The effect of a pollutant on an organism over a relatively l ong tim e, often 1/10 of an organism's lifespan or m o re. Chronic to xicity can m e asure survival, reproducti o n or growth r a tes, or other param e ters to m e asure the toxic effects of a co mpoun d or com b ination of co m pounds. Clean Water Act (CWA) --The Federal Water Pollution Contro l Ac t enacted b y Public La w 92-500, as
am ended by Public Laws 95-21 7, 9 5 -5 76, 9 6 -48 3 , 9 7 -117; USC 1251 et seq.

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

Combined S e wer Ove r fl ow (CSO) --T he event during which excess co m b ined sew age flow caused by inflow is dis c harged from a com b ined sewer, rath er than conve y e d to th e sewage treatment plant because eithe r the capacity of the treatment plant or the co m b ined sewer is ex cee ded. Compliance Inspection

- Without Sampling --A si te visit for the purpose of determ ining the co m p liance of a facility w ith the term s and conditi ons of its pe rm it or with appli cable statutes and regulations. Compliance Inspection - With Samp ling --A site visit to accom p lish the p u rpose of a Co m p liance Inspection - Without Sampling an d as a m i nim u m , sa m p ling and analy s is for all param e ters with lim it s in the perm it to ascertain co m p liance with t hose li m its; and , for m unicipal facilities, sam p ling of influent to ascertain co m p lian ce with the pe rcent rem oval requirem e nt. Additional sampling m a y be conducted. Co mpo s ite S a mple --A mi xture of grab sa m p le s coll ected at the s a m e sa m p lin g point at different ti m e s, formed either b y conti nuo us sam p ling or b y m i xi ng a m i ni m u m of four discrete sa m p l es. May be "time-co m p o s ite"(collected at constant tim e interval s) or "flow- proporti onal" (collected either as a constant sample volum e at tim e intervals proporti on al to stream flow, or colle cted b y incre asing the volum e of each aliquot as the flow increased while maintaining a constant time interval between the aliquots. Constructio n Activity --Clearing, grading, excavation and any ot her activity which disturbs the surface of the land. Such activities m a y include road build ing, construction of residential houses, office buildi ngs, or industrial bui ldings, and de m o lition activity. Continuous Monitoring –Uninterrupted, unless otherwise noted in the perm it. Critical Con d ition --The tim e during which the co m b ination of receiving water and waste discharg e conditions have the highest potential for causing toxi city in the receiving water environm ent. This situation usually occurs when the fl ow within a wat e r body is low, thus, its ability to dil u te effluent is reduced. Dilution Factor --A m e asu re of the am o unt of m i xing of effluent and receiving water that occurs at the boundar y of th e m i xing zone. Expressed as the inverse of the effluent fraction e.g., a dilution factor o f 10 m eans the effluent com p rises 10% by volum e and the receiving water 90%. Engineering Report --A docum ent which thorou g h l y exam ines the engineering and adm i nistrativ e aspects of a particular domestic or industrial wastewater facility . The report shall contain the appropriate in formation required in WA C 173-2 40-0 60 or 173- 24 0-130. Fecal Coliform Bacteria --Fecal colifor m bact eria are used as indicators of pathogenic bacteria in th e effluent that are harm ful to hum ans. P a thogenic ba cteria in wastewater discharges are controlled b y disinfecting the wast ewat e r . The presen ce of high num b ers of fe ca l coliform ba cteria in a wa ter body can indicate the recent rele ase of untreated waste w at e r and/or the presenc e of animal fe ces. Grab Sample --A single sa m p l e or m e as ure m ent take n at a specific tim e or over as short period of tim e a s is feasible. Industrial User -- A disch arger of wast ewater to the sanitary sewer which is not sanitary wastewater or is not equivalent to sanitary waste w ate r in character. Industrial Wastewater

- - Water or li quid-carried waste fro m i ndustrial or co mmercial processes, as distinct from dom estic wastewater. These wastes ma y result from any process or activity of i ndustr y , manufacture, trade or business, fro m the developm ent of any natural reso urce, or from ani m al operations such as feed lot s , poultry houses, or dair i es. The ter m includes conta m inated stor m w a ter and, also, leachate fro m so lid waste faci lities.

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility
Infiltration and Inflow (I/I) --"Infiltration" m eans the addition of ground water into a sewer through joints, the sewer pipe materi al, cra c ks, and other defects. "Inflow" means the addition of precipitation-caused draina ge fro m roof drains, y a rd drains, base me nt drains, stre et cat ch basin s , etc., into a sewer. Interf eren ce -- A discharge which, alone or in conjunctio n with a discharge or discharges fro m other sources, both: Inhibits or di srupts the POTW, its treat m ent pro cesses or operati ons, or its sl udge processes, use or disposal and; Therefore is a cause of a violation of an y requirem e nt of the PO TW' s NPDES perm it (including an increase in the m a gnitude or duration of a violation) or of the pr evention of sewage sludge use or disposal in c o m p liance with the f o llowing statutor y pro v isions and regulatio ns or perm its issued thereunder (or m o re stringent State or local regul ations): Section 405 of the Clean Water Act, the Solid Waste Disposal Act (SWDA) (including title II, m o re co mm only referred to as the Resource Conservation and Recovery Act (RCRA), and incl uding State regulations contained in any Stat e sludge m a nag e m e nt plan prepared pursuant to sub title D of the SW DA), sludge regulations appearing in 40 CFR Part 507, th e Clean Air Act, the Toxic Su bstances Control Act, and the Marine Protection, Rese arch and Sanctuaries Act. Major Facility-- A facility discharging to surface wat e r with an EP A rating score of > 80 points based on such factors as flow volume, toxic poll u t a nt potential, and pub lic health im pact. Maxim u m Daily Discharge Lim i tatio n --The highest allowable daily d i scharge of a pollutant m e asured during a cale ndar day or any 24-hour period that rea s onably represents the cale ndar day for purposes of sa m p ling. The daily discharge is cal culated as the average m e a s ure m ent of the pollutant over the day

. Method Det ection Level (MDL)-- The minim u m concentration of a subs tance that can be measured an d reported with 99% confidence that the analy t e conc entration is above zero and is determ in ed fro m analy s is of a sa m p le in a given m a trix co ntaining the analy t e. Minor Facility-- A facility discharging to surface wat e r with an EP A rating scor e of < 80 points based on such factors as flow volume, toxic poll u t a nt potential, and pub lic health im pact. Mixing Z o ne --A volum e that surrounds an effluent d i scharge with in which water qualit y criteria may be exceeded. The area of the authorized mixing zone is specified in a facility ' s perm it and follows procedures outlined in State regul ations (Chapter 173-201A WAC). National P o l l utant Discharge Elim ination S y stem (NPDES)

- - The NPDES (Section 402 of the Clea n Water Act) i s the Federal wastewater perm itting sy stem for discharges to navigable waters of the United States . Many state s , including the State of Washington, have been delegated the authority t o issue thes e per m its. N P DES per m i t s issued by Washington State permit writers are joint NPDES/State perm its issued un de r both State and Federal laws. Pass through -- A discharge which exits th e P O T W i n t o w a t e r s o f t h e State in q u antities or concentrations which, alone or in conjunction with a discharge or discharges fr om other sou r ces, is a cause of a vi olation of any requirem e n t of the POT W 's NP DES per m it (inclu ding an increase in the magnitude or duratio n of a violation), or which is a cause of a violation of State water quality standards. pH --The pH of a liquid measure s its ac idity or alkalinit y

. A pH of 7 is defined as neutral, and large variations above or below this value are considered harm ful to m o st aquatic life.

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility
Potential Significant Industrial User --A potential significant industrial user is defined as an Industrial User which does not m e et the criteria for a Si gnificant Industrial User, b u t which discharges wastewater meeting one or m o re of the following crite ria:

a. Exceeds 0.5 % of treatme nt plant design capacity criteria and discharges <25,000 gallons pe r da y or; b. Is a m e mber of a grou p of sim ilar industrial users which, taken t ogether, have the potential to cause pass through or i n terference at th e POTW (e.g. facilities which develop photographic film or paper, and car washes). The Depart ment m a y deter m ine that a dischar ger initially classified as a potential significant industrial user should be managed as a significant ind u s trial user. Quantitation Level (QL)-

- A calculated value five ti mes the MDL (method detection level). Significant Industrial User (SIU) -- 1) All indus trial users su bject to Categorical Pretreatm e nt Stand a rds under 40 CFR 403.6 and 40 CFR Chapter I, Su bchapter N and; 2) Any other industrial user that: discharges an av erage of 25,000 gallons pe r da y or m o re of process wastewater to the POTW (excluding san itary , nonco n t act cooling, a nd b o iler blo w -down wastewater); contributes a process w a s t estrea m that m a kes up 5 percent or m o r e of the average dry weathe r hy draulic or organic capacity of the POTW treat me nt plant; or is designated as such by th e Control Authorit y * on the basis that the industr ial user has a reasonable potential for adversely affecting the POTW's operation or for violating any pretreat ment standard or require m e nt (in accordance with 40 CFR 403.8(f) (6)). Upon finding that the industrial user meeting the criteria in paragraph 2, above, has no reasonabl e potential for adversely affecting the POTW's operation or for vi olating an y p r etreatment standard or requirem e nt, the Control Authorit y* m a y at any tim e, on its own initiative or in response to a petition received fro m an industrial user or P O TW, and in accordance with 40 CFR 403.8(f)(6), deter m ine that such ind u strial user is not a signific a nt industrial user. *The ter m "C ontrol Authority" refers to the Wash ington State Depart m e nt of Ec ology in the case o f non-delegated POTWs or to the POTW in the case of delegated POTWs. State Waters --Lakes, rivers, ponds, st reams, inland wate rs, undergroun d waters, salt waters, wetlands, and all other surface w a ter s and waterco u rses within the jurisdiction of the state of Washington. Storm w ater --That portion of precipitation that d o es not naturall y percolate into the groun d o r evaporate, but flows via overland flo w , interflow, pipes, and othe r features of a stor m wat e r drainage s y stem int o a defined surface water body, or a c onstr ucted infiltration facilit y

. Technology-based Effluent Lim i t --A per m it li m it t h at is based on the ability of a treat ment method t o reduce the pollutant. Total Suspended Solids ( T SS) --Total suspended solids are the particul ate m a ter i als in an effluent. Large quantities of TSS discharged to a receiving water m a y result in solids accu m u lat i on. Apart fr om any toxic effects attributable to substances leached out by water, suspended solids may kill fish, shellfish, and other aquatic organisms by causing abrasive injuries and by clogging the gills and respirator y passages of various aquatic fauna. Indirectly , su spended solids can screen out light and can prom ot e and m a intain the development of no xiou s conditions th roug h ox yge n depletion.

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility
Upset --An exceptional incident in which there is unintenti onal and tem porary no ncom p liance with technology

- based per m it effluent lim it ations because of factors beyond th e reasonable control of the Perm ittee. An upset does not include noncom plian ce to the extent caused by operational error, i m properly designed treat ment facilities, lack of pr eventative m a i n tenance, or careless or i m proper operation. Water Quality-based Effl uent Li mit --A lim i t on the concentration or m a ss of an effluent p a rameter that is intended to prevent the concentration of that parameter fro m exceeding its water quality criterion after it is disc harged into a receiving wat e r.

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

APPEND IX C--TEC HN I CAL C A LC ULAT IONS

Several of the Excel ® spreadsheet tools used to evaluate a di scharger’s abilit y t o m eet Washington State water quality standards can be found on t h e De part ment’s hom epag e at http.www:wa.gov.ecology

.

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

Calculation of seawater fraction of un -ioniz ed amm o nia from Hampson (197 7). Un-ioniz ed am m o nia criteria for salt water are from EPA 440/5-8 8 -0 04.

Based on Lotus File NH3 S ALT.WK1 Revised 19-Oct-93

Notes: Cha m bers Creek W W TF Total Ammonia as N H 3-N INPUT
1. Tem p erature (deg C): 90th-%tile 13.9 7 2. pH: 90th- % tile 7.90
3. Salinity ( g / K g): 10th-% t i l e 27.9 4
OUTP UT 1. Pressure (a t m ; EPA crite ria assu mes 1 at m ) : 1.0
2. Molal Io ni c Strength (n ot valid if >0. 85): 0.57 3 3. pKa8 at 25 deg C (Whitf ield m odel "B"): 9.31 1
4. Percent of Total A m m o nia Present as Unionized: 1.674%
5. Unionized amm onia crit eria (m g un-ionized NH3 per liter) from EPA 440/ 5-88-0 0 4 Acute: 0.23 3 Chronic: 0.03 5
6. Total Amm onia Criteria (m g/L as NH3) Acute: 13.9 2 Chronic: 2.09
7. Total Amm onia Criteria (m g/L as NH3-N) Acute: 11.4 4 Chronic: 1.72

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

Dete rmining the Require ment for Pe r m it Limit s T h rough a Reasonable Potential Determ ination to Violate Sta ndards at the Edge of the Mixing Z o ne.

Based on EPA/505/2-9 0 -0 01 Notes: Chambers C reek WWTF Total Ammonia as NH3-N INPUT Confidence Level and Probabilit y Basis: 0.95 Coefficient of Variation for the Effluent Concentration ( CV ) ( 0.6 or a c a lculated CV if there are more than 10 data p oints ) : 0.39 6 Nu m b er of Effluent Sam p les or Data Points ( ND ) : 66 Hi g hest Effluent Concentration or Value ( HV ) : 44.2 Dilution Factors ( 1/ { Effluent Volum e Fraction }) or p lumes m odel Acute Receivin g Water Dilution Factor: 16.7 Chronic Receivin g Water Dilution F actor: 168 Water Q ualit y Standards ( Concentration ) Acute ( on e-hour ) Criteria: 11.4 4 Chronic ( n-d a y) Criteria: 1.72 U p strea m Re ceivin g Water Concentration: U p stream Concentration for Acute Conditi on ( 7 Q 10 ) : 0.02 85 U p stream Concentration for Chronic Condition ( 7 Q 10 ) : 0.02 60 MECB: 1-9 d a ta p oints , hi g hest value b y 2 ; 10 -5 0 th e h i g hest value ; >50 OUTP UT Percentile Re p resented b y the Hi g hest Concentration in Data Se t (p n ) = (1 - confidence level)^1/ND 0.95 562 482 7 Norm al Di stribution Value for 95th Percentile 1.644853476 Norm al Di stribution Value for 96th Percentile 1.70202646
 2 = ln(CV 2 + 1 ) 0

. 1 4 567 140 4 C95 = ex p( 1. 645Si g m a -0.5Si g ma ^ 2 ) 1

. 7 4 186 131 5 C96 = ex p( 1. 702Si g m a -0.5Si g ma ^ 2 ) 1

. 7 8 028 850 4 Reasonable P o tential Multi p lier = C95/C96 1 .0 M a x i mu m E x p ected Concentration of P o llutant in Effl uent ( MEC ) : 4 3

. 2 459 514 2 Acute - Concentration of P o llutant at the Ed g e of the Mixin g Z one ( CP ) : 2 .61 637 134 2 Chronic - Co ncentration of Pollutant at t h e Ed g e of the Mixin g Zone ( CP ) : 0 .28 326 161 6 Reasonable P o tential to Violate Acute C r iteria at the Ed g e of the Mixin g Z one NO Reasonable P o tential to Violate Chronic Criteria at the Ed g e of the Mixin g Z one NO

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

Dete rmining the Require ment for Pe r m it Limit s T h rough a Reasonable Potential Determ ination to Violate Sta ndards at the Edge of the Mixing Z o ne.

Based on EPA/505/2-9 0 -0 01
Notes: Cha m bers Creek W W TF Co pp e r I N P U T Confidence Level and Probabilit y Basis: 0.95 Coefficient of Variation for the Effluent Concentration ( CV ) ( 0.6 or a c a lculated CV if there are more than 10 data p oints ) : 0.35 96 Nu m b er of Effluent Sam p les or Data Points ( ND ) : 15 Hi g hest Effluent Concentra t ion or Value ( HV ) : 22 Dilution Factors ( 1/ { Effluent Volum e Fraction }) or p lumes m odel Acute Receivin g Water Dilution Factor: 16.7 Chronic Receivin g Water Dilution F actor: 168 Water Q ualit y Standards ( Concentration ) Acute ( on e-hour ) Criteria: 4.80 Chronic ( n-d a y) Criteria: 3.10 U p strea m Re ceivin g Water Concentration: U p stream Concentration for Acute Conditi on ( 7 Q 10 ) : 0.66 00 U p stream Concentration for Chronic Condition ( 7 Q 10 ) : 0.66 00 MECB: 1-9 d a ta p oints , hi g hest value b y 2 ; 10 -5 0 th e h i g hest value ; >50 OU TP U T Percentile Re p resented b y the Hi g hest Concentration in Data Se t (p n ) = (1 - confidence level)^1/ND 0.81 896 372 7
Norm al Di stribution Value for 95th Percentile 1.644853476 Norm al Di stribution Value for 82th Percentile 0.911422878

 2 = ln(CV 2 + 1 ) 0

. 1 2 160 873 9 C95 = ex p( 1. 645Si g m a -0.5Si g ma ^ 2 ) 1

. 6 6 995 427 8 C82 = ex p( 0. 911Si g m a -0.5Si g ma ^ 2 ) 1

. 2 9 308 530 1 Reasonable P o tential Multi p lier = C95/C82 1 .3 Maxim u m Expected Concentration of P o llu tant in Effl uent (MEC): 28.4 118 875 2
Acute - Concentration of P o llutant at the Ed g e of the Mixin g Z one ( CP ) : 2 .32 178 967 2 Chronic - Co ncentration of Pollutant at t h e Ed g e of the Mixin g Zone ( CP ) : 0 .82 518 980 7 Reasonable P o tential to Violate Acute C r iteria at the Ed g e of the Mixin g Z one NO Reasonable P o tential to Violate Chronic Criteria at the Ed g e of the Mixin g Z one NO

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

Sum m a ry of Cham ber Creek Outfall Evaluation f r om ReRating Investigati o n
Ambient Vel o city Near C h amber C r e e k WWTP Outfall

Current Condition 36.3-ft Velocity, cm/s 73.3-ft Velocity, cm/s Acute #1, (10 th Percentile) 3 1.5 Chronic, (50 th Percentile) 8.2 6.7 Acute #2, (90 th Percentile) 21.7 18.3

Sum m a ry of Mixing Z o ne Evaluation Critical Condition Criteria

D ESCRIPTIO N 1 P ARAMETE R A CUTE C HRONIC S OURCE

Density Profile Worst case of the max and min stratification- least m i xing Worst case of the max and min stratificat ion- least mixing 1999DOE/EvansHam ilton Am bie n t D a ta Current Velocity Worst case of the 10 th an d 90 th percentile velocity 50 th percentil e velocity 1999 EvansHam ilton Am bie n t D a ta Critical Water Depth Mean lower low water (MLLW) Mean lower low water (MLLW) NPDES Permit

Effluent Te m p erature 10 th percentile of wet weat her flow time period=12. 8 o C 10 th percentile of wet weather flow time

period=12.8 o C Plant Records

Mixing Zone Size Ten percent of the chronic boun dar y 31-ft Cy li nder with a radius= 200 ft + MLL W and height=MLLW 310-ft NPDES Permit

Plant Flow Rate I f f l o w r a t e < 85% dr y weather design flow, then use the highest daily m a x for last 3y rs. If flow rate > 85%, then us e a peaking factor applied to d ry weather desig n flow (existing and future). I f f l o w r a t e < 85% dr y weather desig n flow, then use highest monthl y avg. If flow rate > 85%, then us e

dr

y weather design flow (existing and future). Plant Records

1 So urce-DOE Perm it Writer’s Manual, July 19 98.

Outfall Diffuser Input Pa ramet ers for PLUMES Model

C RITERIA Value

Nu m b er of Ports 8 Port Spacing 16 feet

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility
Average Port Depth 110 feet ML LW Port Diam eter 0.99 feet Vertical Disc harge Angle 0 degrees Port Contraction Coefficient 0.8 (bell shaped)

Port Elevatio n Above Bottom 8 feet

The diffusion port coefficient used in th e PLUMES m odel was 0.0003 based on a study of sim ila r outfall diffusers, perfor m ed by Baum g a rtner, Frick, Roberts, and Bodeen, in Ju ne 19 93. T h e m o d e l is configur ed such that all ports are as su m e d t o discharge on the sa m e si de of the diffuser.

Acute and chronic diluti on factors were determ ined by var y in g the treatment plant peak m onthl y flow rate from 7 to 27 m gd. Peak monthl y flow r a te of 27 m gd and peak dail y flow rate of 43 m gd was used for dilution factors co m p ariso n s. The following table summa rize s the critical conditions, parame ters used, and diluti on f actors for a peak m onth flo w rate of 27 m gd.

Sum m a ry of Critical Conditions

D ESCRIPTIO N

P ARAMETER A CUTE C HRONIC Density Profi l e DOE Station GOR001 Jul y Density Data DOE Station GOR001 August Density Data Current Velocity 10 th percentile 50 th percentile

Critical Water Depth 110 feet 110 feet

Effluent Te m p erature 12.8 o C 1 2

. 8 o C Mixing Z one Size A cy lin der with a radius of 31 feet A cy lin der with a radius of 310 feet Plant Flow Rate Peak daily fl o w ranging fro m 11m gd to 43 m gd Peak m onthl y flow ranging from 7m gd to 27 m gd

Dilution Factors for Peak Month Effluent Flow Rate of 27 mgd

(Peak Day Fl ow Rate of 4 3 m g d).

Tria

l Nu m b er of 11.9-i n Dia m eter

Ports Density Profi l e Velocity 36.3 ft Velocity 73.3 ft Acute
Dilution Factor 1 Chronic
Dilution
Factor 1

1 8 DOE-July Density 3 1

. 5 1 6

. 7

-

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

2 8 D O E

- A u g u s t Density 8

. 2 6

. 7

- 1 6 8

1 Based on critical conditions for each mixing zone boundar y as provided above. At a peak m o nth effluent fl ow rate of 27 m gd (peak day flow of 4 3 m gd), the acu te and chroni c dilution zone factors are 16.7 and 1 68, for th e acute and chronic zones resp ectively

.

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

APPENDIX D--RESP O NSE TO COMMENTS
This response to comments (RTC) is an appendix to the fact s h eet for the above referenced National Pollutant Discharge Eli m i n ation Sy stem (NP D ES) pe r m it. The RTC su mmarizes co mments rec e ived during th e 30 -day public n o tice and comment perio d on the draft perm it, and provides the Department’s response. Al l changes to t h e draft per m it are noted b e low. The Depart m e nt has determined to issue this per m it as revi sed.

Co mments were received from Depart ment of H ealth (DOH) and P i erce County Public Utiliti es. Depart ment of Health (DOH) Co mments:

1. Comment:

Fecal coliform te sting frequenc y should be increase d rather than reduced at the Cha m bers Cree k WWTP. Flows to this facility have been stea dily increasing over the past y ears, and Pierce Count y i n ten d s to direct m o re flows to the plant u nder its regio n al plan in t h e near future. The NPDES per m it issued for t h is plant in 1990 requir ed fecal colifor m t esting five day s each week. However the draft per m it has reduced t h is testing to only three day s each week . My copy of the Ecolog y Per m it Writers Manual reco mmends (min im u m m onitoring) dail y (seven day s per week ) testing of fecal coliform s for activated sludge pl ants with greater than 5.0 m gd average design flow. The average daily design flow listed 12 y ear s ago in their p e rm it is 18.0 m gd. Therefore, the fecal coliform testing f r equency at th at ti m e should have been seven day s each week. Given the significant increase in plant flows, and the rela tively short distance fro m this plant's outfa ll to harvestable s h ellfish resources, we re co mmend that the fec a l coliform t est ing frequency be increased to seven day s e ach week (rat h er than reduced to three) . The increas ed fecal coliform testing frequency will be especially useful for m onitoring the effectiveness of their UV disinfection sy stem

. You can re ad more details o f the potential i m pact of this dischar ge on nearby shellfish resources i n m y evaluation report of this facility in April 1999. Thank y o u very m

u ch for y o u r consideration of this reco mmendation.
Response:

The Cha m ber s Cre e k WWTF was eligible for a re duction in frequency for fecal coliform t e s ting due to the ratio of their monthl y averag e effluentco ncentration to their avera g e m onthly per m it lim it. However, in light of the Department of H ealth’ s concern over shellfish beds in the area a nd a new ultravi o let disinfection sy stem f

o r the Cha m bers Cre e k WWTF the f r equency for feca l coliform testi ng will be set at five times per week for the next perm i t term

. Pierce County Public Works and Utilities Commen ts:

2. Comment:

S2A. Monit o ring Schedu l e , pages 7 an d 8. Most of the param e ters in this section have reduced
m onitoring schedules base d on the compliance histor y of the Cha m b e rs Cr eek WWTP. The draft per m it proposes daily m onitoring for te m p eratur e, pH and dissolved oxy ge n. The County proposes to have these para meters r e duced to the sa me frequency as effluent CBOD and Suspended Solids m onitoring. There have been no exceedance s of the pH effluent lim it ations for Cham bers Creek and no co ncerns raised related to the te m p erature a nd dissolved oxy g en data.

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce Coun ty Chambers Creek Wastewater Facility

Response: The Department acknowledges the exem plary co m p liance histor y of t h e Cham bers Creek WWTF. The Department looks at compliance hi story when determining testin g frequencies for para m e t e rs s u ch as BOD 5 , TSS, Amm onia- N, and Fecal Coliform

. The Depart ment has not applied reduced m onitoring based on com p lianc e hist ory to parameter s such a s te m p er ature , pH, and dissolved ox ygen. No change to per m it.

3. Comment: Effluent Mixing Stud y – T h e County com p leted an effluent m i xing ration study in 1994 . While the Count y has a valid study that could be adapte d to provi de m i xi ng rations f o r increasing flows, the County is in agreem ent with this extr a effort to up date the m i xing ratio stud y

.
Response:

Co mment not ed.

4. Comment: Chronic toxicity effluent characterization – The County has previo usly con ducted chronic toxi city effluent characterization fo r the Chambers Creek WWTF. The County is in agreem ent with this additional eff o rt to update th e char acterization with m a rine organisms.
Response:

Co mment not ed.

5. Comment: Page 5, Industrial discharges – Pierce Power d eco mmissioned their facility and term inated all operations on Septem ber 27, 20 02. This disch arger should be rem oved from the fact sheet. Frederickson Power generates electrical power throug h combustion tur b i n es with a stea m recovery pr ocess subject to categorical industr y standards. This SIU took over the site and
assu med the per m it of the former Tenaska generating facility

.

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### Fact Sheet for NPDES Permit No. WA0039624 Pierce County Chambers Creek Wastewater Facility

8/21/2003 Page 33 Response: The fact sheet will be updated to reflect the above changes.

6. Comment: The announcement of availability of draft permit refers to the City in the tentative determinations section. This should refer to Pierce County.
Response: The announcement for copies of the draft permit will refer to the County rather than the City in future announcements.