FAC T SHEE T An d NPDE S WASTEWATE RDISCHARG E PERMI T EVALUATIO N

Departmen t

o f Environmenta l Qualit

y Wester n Regio n - Sale mOffic e 75 0 Fron t Stree t NE , Suite 120 , Salem , O R97301-103 9 Telephone : (503 ) 378-824 0 PERMITTEE : Cit y o f Corvalli s P.O . Bo x 108 3 Corvallis , O R97339-108 3 Fil e Number : 2015 1 SOURC E LOCATION : P.O . Bo x 108 3 SOURC E CONTACT : DanHanthor n Telephon e Number : 541754-175 7 PERMI T WRITER : Robert Dicks aTelephon e Number : 50 3 378-503 9 PROPOSE D ACTION : Renewa l o f aNationa l Pollutan t

Discharg e Eliminatio n Syste m(NPDES ) wastewate r

discharg e permi t SOURC E CATEGORY : Majo r Domesti c TREATMEN T SYSTE M CLASS : Leve l IV COLLECTIO N SYSTE M CLASS : Leve l IV PERMI T APPLICATIO N DATE : Decembe r 31 , 200 3 PERMI T APPLICATIO N NUMBER : 98379 3 

### BACKGROUN D Introductio n Cit y o f Corvalli s operate s awastewate r treatmen t facilit y locate d i n Corvallis , Orego

n (see Figure 1) . Wastewate r i s treated an

d discharge

d to Willamett

e Rive r i n accordanc e wit

h Nationa l Pollutan t Discharge Eliminatio

n Syste m (NPDES ) Permi

t numbe r 101714 . Th

e Permi t fo r the facilit y wa s issued o

n August 9,199 9 an d expire d o n June 30 , 2004 .City o f

Corvalli s Evaluatio n Repor t Pag e 2 Figur e 1

/ / put' / V ; • // /

A y !•; > L ' f -^fes^pBa^ .

:-/3 " W ." 7 1 .T7- : ,-7 " 

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### - !^ : 

### '<^,----^ v 

### '"^#W : 

### ^A

_ 5 7 £ ' . - •

iVr' " v ^ s 

# Tiam ; m^ui/Am.

-&M H . Th e Departmen

t receive d arenewa l application o

n Decembe

r 31,2003 . Th

e permi t shal l not b e deeme d to expir e unti l final action ha s bee

n take n o n th e renewa

l application a s pe

r Orego n Administrativ e Rule s (OAR ) 340-045 - 0040 . A renewa

l permi t i s necessaiy to discharg e to stat e waters pursuan

t to provision s o f

Orego n Revise d Statute s (ORS ) 468B.05 0 an

d th e Federa l Clea n Wate r Act . Th e Departmen

t propose s to rene

w the permit . Thi s permi

t evaluatio n repor

t describe s th e basi s an

d methodolog

y used i n developing th e permit . Thi s permit

i s ajoin t federa l an d stat e permi t an d subjec t to federa l an d stat e regulations . Th

e Clea n Wate r Act , the Cod e of Federa l Regulations , an

d numerou s guideline s o

f the Environmenta

l Protectio n Agenc

y provid e th e federa l permit requirements . Th

e Orego n Revised Statutes , Orego

n Administrativ e Rules , an

d policie s an

d guideline s o

f th e Departmen

t of Environmenta

l Qualit y provid e th e stat e permittin g requirements . 

### FACILIT Y DESCRIPTIO N Th e curren t treatmen t facilit y consist s of

a n influen t pum p station , primar

y screenin g an

d grit removal , primar

y settling , tricklin g filters wit

h activate d sludg e biologica l secondar y treatmen t an d secondai y clarification . Afte r secondar y treatmen t th e wastewate

r i s disinfected wit

h chlorine an

d dechlorhlate d wit

h sodiu mbisulfit e prio r t o discharg e t

o th e Willamett

e Rive r throug h asubmerge

d multi-por

t diffuser . Th e completion of

th e combine

d sewe r overflow (CSO ) project

ha s adde d additiona

l facilitie s to provid

e primar y treatment , storage , an

d disinfectio n of

combine d sewage . I

n addition , th e treate d combine d sewag e i s dechlorinate d wit

h sodiu mbisulfit e to compl y wit h chlorine residua

l requirement s prior

to it s discharg e to the Willamett e River . Th

e CS O remediatio n collectio n an d facilitie s wer

e placed int

o servic e i n Octobe r 2000 . OpCertClassWorkshee t

(Rev . 12/03/2008 )Cit y o f

Corvalli s Evaluatio n Repor t Pag e 3 Communit y investmen t

i n th e projec t

wa s $30.1M . Th e propose d NPDE S permi t wil l cove r

anumbe r o f discharges , t o water s o f

th e Stat e o f

Oregon . Th e variou s point s o f discharg e ar e liste d o n th e cove r pag e o f th e propose d permit . Outfall s 00 1 an d 00 2 consis t o f secondar y treate d wastewater . Outfal l 00 1 i s adiffuser locate d i n th e Willamett e River . Treate d effluent flow s ou t throug h Outfal l 00 1 b y gravity . Durin g period s o f hig h rive r

flow , th e rive r

elevatio n cause s gravity flow throug h th e diffuse

r t o b e impede d an d th e us e o f Outfal l 00 2 i s necessaiy . Outfal l 00 2 i s locate d adjacen t t o th e treatmen t plan t an d enter s Dixo n Creek , asmal l tributar y t o th e Willamett e River . Outfal l 00 2 i s onl y use d a s a n emergenc y outfal l whe n th e rive r stag e elevatio n o f

th e Willamett e Rive r

rise s abov e 20 6 ft

abov e mea n se a leve l (msl) . Whe n th e Cit y doe s hav e t o us e Outfal l 002 , th e duratio n o f us e i s agraduate d base d o n th e elevatio n o f th e rive r level . Th e us e o f

Outfal l 00 2 ha s significantl y decrease d sinc e th e Cit y implemente d th e ne w CS O treatmen t facilitie s an d th e las t

tim e th e Cit y ha d t o utiliz e Outfal l 00 2 wa s durin g th e winte r seaso n i n 2006 . Outfall s 003 , 005 , an d 007 , ar e CS O overflo w points , Discharge s fro mthes e outfall s wil l b e infrequen t du e t o th e recen t constructio n o f

th e ne w CS O treatmen t

facilities . A s aresul t

o f th e completio n o f

thes e facilities , th e CS O Outfall s 00 4 an d 00 6 hav e bee n eliminated . Outfall s 008 , 009 , an d 011 , wer e previousl y liste d a s emergenc y overflow s point s a t pum p stations . Howeve r

th e Department' s Bacteri arul e i n OA R340 - 041-0009 , prohibit s discharge s o f ra w sewage . Therefore , thes e emergenc y overflo w point s hav e bee n remove d fro mth e propose d NPDE S permit . Outfal l 010 , th e Bec aStree t pump statio n ha s als o bee n eliminated . Outfal l 01 2 i s th e discharg e fro mth e combine d sewag e treatmen t syste man d i s adiffuse r

locate d i n th e Willamett e Rive r

downstrea mfro moutfal l 001 . Th e majo r

treatmen t

proces s use d i s activate d sludge . Th e enginee r wh o designe d th e facility determine d th e averag e desig n dt y weathe r flow. I t i s th e estimate d maximu mflow durin g Ma y 1 t o Octobe r 3 1 (expresse d a s a dail y averag e flow), a t

whic h th e desig n enginee r expect s th e treatmen t

facility can stil l consistentl y mee t al l effluen t limits . Th e di y weathe r

flows d o no t

includ e th e hig h level s o f infiltratio n an d inflo w tha t ar e associate d with th e winte r i n Oregon . Therefore , th e desig n di y weathe r flows ar e use d mostl y t o estimat e ho w muc h treatmen t capacit y ther e i s fo r

organi c loads . Fo r

thi s facility , th e averag e desig n dt y weathe r flo w i s 9. 7 millio n gallons/day (MGD) . Th e curren t

actua l di y weathe r

flow fo r May 1 t o Octobe r

31 , for th e pas t tw o years , i s 7.4 1 mgd . Base d o n th e curren t

flows , thi s facility i s a t

76 % o f hydrauli c treatmen t

capacity . Sinc e th e las t

permi t issuanc e i n 1999 , th e City o f

Corvalli s ha s continuall y deal t wit h hydrauli c capacit y an d treatmen t issue s throug h ongoin g maintenanc e an d syste mimprovements . Collectio n syste mimprovement s durin g th e permi t perio d hav e increase d firmcapacity an d reduce d inflo w an d infiltration . Fiv e mile s o f sewe r lin e wer e rehabilitate d o r replaced ; tw o separate lif

t station s wer e replaced ; on e new , additional sewe r lif t station ; an d 72 6 manhole s sealed . Conveyanc e syste mimprovemen t expens e totale d $21.2M . Treatmen t facilit y improvement s sinc e 199 9 enhance d capacity , reliability and performance . Improvement s included : tw o gravity sludg e thickeners , additional anaerobi c digester , disinfectio n facilities , electrica l gea r replacemen t

an d seismi c upgrades . Al l treatmen t facilit y improvement s totale d $14.2M . Th e curren t

actua l averag e we t

weathe r flow (Novembe r

1 throug h Apri l 30) , fo r

th e pas t tw o years , i s 12. 0 MGD . Th e pea

k da y fknv ove r

th e pas t tw o year s i s u p t o 20. 1 MGD . Se e th e sectio n o n Inflo w an d Infiltratio n for afurthe r discussio n o f

winte r flows an d hydrauli c capacit y issues . Biosolid s Managemen tan d Utilizatio n Th e permittee' s curren t

biosolid s managemen t

pla n wa s approve d Augus t 6 , 1999 , an d update d an d approve d b y DE Q i n Januar y 2007 . Th e update d pla n wil l b e availabl e for revie w an d commen t

a s par t o f th e permi t document s for

Publi c Notice . Al l biosolid s mus t b e manage d i

n accordanc e with th e Departmen t approve d OpC e rtClassWorksheet

(Rev . 12/03/2008 )Cit y o f

Corvalli s Evaluatio n Repor t Pag e 4 Biosolid s Managemen t

Pla n t o ensur e complianc e with th e biosolid s regulation s (OA R340-050) . Afte r treatmen t necessai y t o compl y with vecto r attractio n an d pathoge n reductio n requirements , th e Clas s B biosolid s ar e beneficiall y lan d applie d o n site s i n Bento n Count y an d Lin n County . An y future lan d applicatio n site s mus t confor mt o th e sit e selectio n criteri ai n th e Biosolid s Managemen t Pla n an d mus t

b e i n Lin n o r

Bento n Counties . Th e permitte e generate s sludg e fro mth e primar y sedimentatio n tank s an d th e secondai y clarifiers . Th e sludg e i s thickene d i n gravit y thickener s the n pumpe d t o on e o f th e anaerobi c digesters . Th e stabilize d biosolid s ar e store d i n tw o facultativ e lagoon s prio r t o spreadin g o n agricultura l lan d durin g th e month s o f Jun e throug h October . Thi s permi t

require s reportin g fou r

time s pe r year o f th e method s use d t o compl y with vecto r attractio n an d pathoge n reductio n requirements . I t als o require s th e submitta l o f an annua l summary repor t Th e permitte e produce s approximatel y 85 0 dry metri c ton s o f biosolid s pe r

year . Th e Cit y conduct s regula r chemica l testin g o f

biosolid s (se e Tabl e 1) . Testin g include s analyse s for nutrient s an d 1 0 metals . Base d o n th e analyses , ther e ar e n o know n potentia l impact s fromth e curren t lan d applicatio n program . Tabl e 1 - Biosolid s Metal s Result s Base d o n 200 9 Annua l Repor t Paramete r Arseni c Cadmiu m Chromiu m Coppe r Lea d Mg/dryK g

6.1 0 4.1 7 7 6 65 5 9 4 §503.1 3

Table 3 Limi t 4 1 mg/k g 3 9 mg/k g N o limi t 150 0 mg/k g 30 0 mg/k g Paramete r

Mercury Molybdenu m Nicke l Seleniu m Zin c Mg/dr y

-'"..•Kg : 3.1 3 5.5 4 2 5 5.9 6 85 2 §503.1 3

Tabl e 3 Limi t 1 7 mg/k g N o limi t 42 0 mg/k g 10 0 mg/k g 280 0 mg/k g Inflo w an d Infiltratio n (I/I ) Th e City o f

Corvalli s sanitar

y sewag e collectio n syste mi s acombine d system . Part o f th e collectio n syste m receive s stormwate r

an d sewage , and durin g significan t rainfal l event s CSO s occur . Anothe r sourc e o f non-sewag e flow i s Inflow/Infiltratio n (I&I) . I& I i s aconcer n du e t o th e fac t

tha t i t ca n negativel y affec t

treatmen t

plan t performanc e an d overwhel mth e collectio n an d treatmen t syste mcapacity . Inflo w i s stormwate r that enter s th e collectio n syste mthroug h surfac e leak s a t acces s points , suc h a s manhole s o r pum p stations . Infiltratio n i s th e entr y o f groundwate r

a t cracke d o r

broke n pipes . Whil e inflo w ca n typicall y b e controlle d fo r th e mos t part , infiltratio n i s an on-goin g battl e for

th e cit y a s th e collectio n syste mages . I t i s economicall y an d practicabl y unrealisti c t o expec t tha t al l infiltratio n coul d b e removed . Rather , th e Cit y mus t continuall y evaluat e th e infiltratio n source s an d correc t thos e that offe r th e greates t

cost-effectiv e reduction . Th e propose d renewal permi t require s that

th e city maintai n a

n on-goin g I& I Reductio n Program . Annual report s whic h summariz e th e statu s o f th e I& I removal effort s mus t b e submitte d t o th e Department . Industria l Pretreatmen t Th e City o f

Corvalli s implement s a

n industrial pretreatmen t

programapprove d b y th e Departmen t o n Jun e 2,1983 . Federa l an d stat e pretreatmen t requirement s wer e include d i n th e NPDE S permi t fo r thi s facilit

y whe n th e existin g permi t wa s issued . Th e City o f

Corvalli s wo n first

plac e i n EPA' s Nationa l Pretreatmen t Awar d fo r excellenc e fo

r 200 6 for smal l pretreatmen t

programs . Th e Cit y o f Corvalli s currentl y permit s thre e significan t industria l use r

(SIUs ) o f whic h tw o ar e federall y designate d categorica l industrial users . A fourt h permitte d use r

i s acategorical industria l user (CIU ) bu t

no t aSIU . Annua l pretreatmen t

programreport s are submitte d yearly . A Pretreatmen t Complianc e Audi t

o f th e industria l pretreatmen t

programwa s conducte d b y th e Departmen t i n September

2005 . Th e primar

y focu s o f th e audi t wa s t o OpC e rtClassWorksheet

(Rev . 12/03/2008 )Cit

y o f Corvalli s Evaluatio n Report Pag e 5 revie w an d asses s the cor

e pretreatmen

t progra mfunctions , sourc e files, enforcemen t actions , pollution preventio

n effort s an d compliance status . A s aresul t of thi s audit , the Departmen

t determine d the pretreatmen

t progra mi s functionin

g i n compliance wit

h th e federa l pretreatmen

t requirements an

d th e NPDE

S pretreatment-related permi t conditions . Th

e Departmen

t identified , required an

d recommende

d action s intende

d to furthe r improv e th e industria

l pretreatmen

t program . Overall , th e City' s pretreatmen t progra mi s a n exceptionall

y wel l manage d progra mi n al l aspects . Groundwate r Issue s Th e treatmen t plan t i s constructe d entirel

y o f imperviou s structures . I

t i s not anticipate d tha

t th e treatmen

t proces s an d discharg e t

o surfac e water s wil l caus e groundwate r impacts . Schedule A of

the propose d permi

t prohibit s advers e impacts t

o groundwater . I

n addition , th e Cit

y of Corvalli s i s evaluatin g WWR P effluen t discharg e alternative s to compl y wit h th e Willamett

e Rive r Tota l Maximu mDaily Loa

d (TMDL ) fo r temperature . Thos e alternative s includ e evaluation s o f

subsurfac e hyporhei c discharge s t o th e Willamett e River . Should an y alternativ e b e selected tha t include s asubsurfac e discharge , th e permitte e wil l need to compl y wit h nitrate limit s associate d wit h th e Departmen

t designated Souther

n Willamett

e Valley Groundwate

r Managemen

t Are a(GWMA) . Stormwate r Issue s Genera l NPDES permits fo

r stormwate r ar e required fo

r wastewate r treatmen t facilitie s wit

h adesig n flow of greate r tha n 1 MG D if stormwate r i s collecte d an d discharge

d fro mthe plan t site . However, all rai

n wate r a t thi s facilit y flows throug

h the treatmen

t processe s an

d i s not discharged a s stormwater . Outfall s Th e curren t NPDE S Permi t allow s the treatmen

t facilit y to discharg e treated effluen t int o th e Willamett

e Rive r adjacen t t o th e plan t a t Rive r Mile 130. 8 (Outfal

l 001) , an d int o Dixo n Cree k a t Rive r Mil e 0. 1 (Outfal

l 002) . Outfal l 00 1 (Willamett

e Rive r outfall) i s locate

d a t approximatel

y Latitud e 44 ° 34 ' 29 " North , Longitud e 123 ° 15 ' 2 " West . Treated , disinfecte d an d dechlorinate

d effluen t i s discharged throug

h Outfal l 00 1 t o th e Willamett

e River . Whe n the rive r elevatio n cause s gravit

y flo w throug h Outfal l OOlt o be impeded , the us e of

outfal l 00 2 to Dixo n Cree k i s necessaiy . Th e existin g permi t identifie s five combine

d sewe r overflo w point s to the Willamett

e Rive r a t Rive r Mile s 131.3 , 131.4,131.6 , 131.7 , an

d 132.2 . Tw

o of thes e overflo

w point s have bee

n eliminate d sinc e the issuanc e o

f th e curren t permit . Th

e Departmen

t propose s to retain th

e othe r three combine

d sewe r overflo w points . Th e existing permi

t als o identifie s Outfal

l 013 , whic

h i s used fo

r th e discharg e o

f groundwate

r fro mdrain s below th e CS O storag e lagoon . Thi s natura l underdrai n groundwate

r i s necessaiy to protect

the CS O storag e lagoo

n liner . Th e wate r i s not contaminate

d an d therefor e doe s no t hav e an y effluen t limitation s however, the Cit y continue s to monito r th e wate r fo r flow an d conductivit

y twic e ayea

r t o ensur e tha t the line r i s not leaking . O

n th e basi s tha

t thi s i s natura

l groundwate

r tha t i s no t contaminate

d o r co-mingle d wit h the treatmen

t process , th e Departmen

t i s proposin g t o remov e thi s outfal

l fro mth e permit . Th e Cit y of Corvalli s WWR

P i s als o lookin

g a t variou s treatmen

t alternative s to compl

y wit h the Tota l Maximu m Dail y Loa d (TMDL ) Wast e Loa d Allocatio n (WLA ) fo r temperature . Par

t of th e treatmen

t alternative s ma

y includ e utilizing recycle

d wate r fo r irrigatio n throug h lan d application . While the Cit y ha s not mad e afinal decision a

s to whic h Clas s of recycle d wastewater , dependin

g o n the chose

n alternative , th e Cit

y i s proposin

g to trea t th e wastewate r to eithe r Clas s A , Clas s B , Clas s C , o r Clas s D standard s i

n accordanc e wit

h OA R340-05 5 an

d confor m to aRecycle

d Wate r Us e Pla n approve d b y the Department . OpCertClassWorkshee t

(Rev . 12/03/2008 )Cit

y o f Corvalli s Evaluatio n Repor t Pag e 6 Th e propose d permi t will includ

e Outfal l 01 4 t o allow the permittee to beneficiall y lan d appl y treated recycle

d wastewate r i n accordanc e wit

h OA R340-05 5 durin

g th e summe

r seaso n (Ma y 1-Octobe r 31) . Th e propose d permi t will contai n limits an d monitorin

g requirements fo

r Clas s A , Clas s B , Clas s C , an d Clas s D recycle

d wate r to allow the permittee to compl

y wit h eithe r Clas s of recycle d wate r dependin g o n whic h alternative i s selected . Th e permittee will b e required to stat e the selected alternative an

d Clas s o f recycle d wate r i n the Recycle

d Wate r Use Plan . Th e Recycle d Wate r Us e Pla n mus t be approve

d b y the Departmen

t prio r t o the permittee lan

d applyin g th e treated recycled wastewate

r throug h Outfal l 014 . Followin

g Departmen

t approval , the lan

d application of wastewate r shall confor

mt o th e Departmen

t approve d plan . All recycle

d wate r shal l b e distributed o

n lan d fo r dissipation b

y evapotranspiration an

d controlle d seepage b

y followin g soun d irrigation practice s s o a s to prevent : 1 . Prolonge

d pondin g of treated wastewate

r o n th e groun

d surface ; 2 . Surfac e runof f or subsurface drainag e throug

h drainag e tile ; 3 . Th e creation o

f odors , fly an

d mosquit o breedin g o r otherwis e nuisanc e conditions ; 4 . Th e overloadin

g o f lan d wit h nutrients , organics , o

r othe r pollutan t parameters ; and , 5 . Impairmen

t of existing or

potentia l beneficia l use s of groundwater . 

### RECEIVIN G STREA M Hvdroiogi c Characteristic s Th e outfal l location i s abou

t 3 0 mile s downstrea

mof th e neares t

USG S gag e o n th e Willamett

e Rive r (Gage No . 14166000 ) a t Harrisburg . Severa

l small stream s ente

r th e Willamett

e betwee n th e Harrisbur

g gage an d th e discharg e poin

t an d ad d small amounts o f

wate r t o th e river . Two of

thes e stream s als o hav e gage s (USGS gag e 1417000 0 Long To mRive r a t Monro e an

d USG S gag e 1417100

0 Maiy s Rive

r nea r Philomath) . Th

e drainag e are aof th e combine

d area s i s 397 0 squar

e miles . Low rive r flow was determined using dat afro mth e above gage s fro

m197 0 through th e present . Th e critica l cas e lo w flows fo r th e "summer " season (Ma

y tlyoug h October) , th e "winter " season (Novembe r throug h April) , th e salmonid rearin g an

d migratio n season (Ma

y 1 6 through Octobe

r 14 ) an d th e spawnin

g season (Octobe

r 1 5 throug h Ma y 15 ) wer e calculated . Th

e harmonic mea

n flow i s 762

4 cfs . Seaso n Summe r (Ma y ~ Oct ) Winte r (No v - Apr) Rearing (5/16-10/14 ) Spawnin g (10/15-5/15 ) 1Q1 0 359 0 343 2 360 0 325 3 7Q1 0

368 6 3622 368 6 346 8 30Q5

4109 535 7 412 9 501 9 Th e propose d permi t will allow th e permittee t

o derive th e receiving strea

mflo w rat e fro mcombinin

g the flow rate s fromUSG

S gaugin g station Numbe

r 1416600 0 (a t Harrisburg) , USG

S gaugin g station Numbe

r 1417000 0 (Lon g To mRive r a t Monroe) , an

d USGS gaugin

g station Numbe

r 1417100 0 (Mary s Rive

r nea r Philomath ) o r fromUSG S gaugin g station numbe

r 1417160 0 (Willamett

e Rive r a t Corvallis) . Receivin g Strea m Wate r Oiialit v Th e City' s discharg e i s to the Willamett e Rive r a t Rive r Mil e 130.8 . Th

e discharg e i s within the Uppe r Willamett e sub-basin . Th

e designate d beneficia

l use s of th e receivin g strea

mare : publi c an

d privat e domestic wate r supply , industria

l wate r supply , irrigation , livestoc

k watering , fish an

d aquati c lif

e (including salmoni

d rearing , migration an

d spawning) , wildlif

e an d hunting , fishing, boating , wate r contac t recreation , an

d aestheti c quality . Th

e wate r qualit y standard s fo

r th e Willamett

e Basin (OA

R340-041 ) wer

e developed t

o protect the beneficia l use s o f th e basin . OpCertClassWorkshee t

(Rev . 12/03/2008 )Cit

y o f Corvalli s Evaluatio n Report Pag e 7 Treated wastewate

r i s discharge

d t o the Willamett

e Rive r a t rive r mil e 130.8 . A t thi s location , th e Willamett

e Riveti s wate r qualit y limite d fo r the followin

g parameters : Paramete r Temperatur

e Feca l Colifor m Dissolved Oxyge

n Mercur y Seaso n Summe r Winter/Spring/Fal

l Winter/Spring/Fal

l Yea r roun d Temperature Issues Wate r temperatur

e affect s th e biologica

l cycle s of aquati c specie s an

d i s acritica

l facto r i n maintaining an

d restorin g health

y salmonid population s throughou t the state . I

t i s th e polic y o f

th e Environmenta

l Qualit y Commissio

n (EQC ) to protect

aquati c ecosystem s fro

madvers e temperatur

e change s caused b

y anthropogeni c activities . Th e purpos e of

th e temperatur

e criteri aliste d i

n OA R340-041-002 8 i s to protect designated beneficia l use s tha t ar e temperatur

e sensitive , including salmonid s i n water s of

th e State . Th e Departmen

t utilize s Fis h Us e Designatio n map s an d Salmo n an d Steelhea d Spawnin g Us e Designation s map s t o identif

y applicabl e temperatur

e criteri afo

r eac h basin . Th

e Willamett

e Basin map s ar

e contained i

n OA R340-041 , Figure s 340

A an d 340B , respectively . According t o th e approved us e designation maps , salmo n an d steelhea d spawnin g i s adesignate d us e of

the Willamett

e Rive r fro mOctobe r 1 5 through Ma

y 15 . During thi s period , th e applicabl e temperatur e criterio n i s 1 3 °C . Fo

r the remainde

r of th e year , salmo

n an d trout rearin g an d migratio n i s th e designate d us e wit h a n applicabl e temperatur

e criterio n o f

1 8 °C . Th e Department' s Lis t

of Wate r Qualit y Limited Wate

r Bodie s (als o calle d th e 303(d) List) fo r 2004/200 6 indicate s th e Willamett

e Rive r i s wate r qualit y limited fo

r temperature . Th e Willamett e Tota l Maximu mDail y Loa d (TMDL ) was issue d b

y th e Departmen

t o n Septembe

r 21,200 6 an

d approved b

y EP A o n Septembe

r 29 , 2006 . Th e TMD L deal s wit

h temperatur

e issue s i n mos t of th e Willamett

e Basin including thi s segmen t of th e Willamett e River . Th e TMD

L determined th e temperatur e standar d i s violate d fro

mApri l 1 throug

h Octobe r 31 , Th e TMD L include s Wast

e Loa d Allocation s (WLA

) fo r th e discharg e fro

mth e Cit y of Corvalli s Wastewate

r Treatmen t Plan t fro mApri l 1 through Octobe

r 31 . Thi s permi

t include s limitation s tha

t ar e i n accordanc e wit

h th e WLA . I n addition , th e Departmen

t evaluate d th e discharg e t o ensur e complianc e wit

h th e temperatur

e standar d during th e res t of th e yea r (Novembe

r 1 throug h Marc h 31) . Th e evaluation (se e Attachmen t #1 ) determine

d ther e wa s n o reasonabl e potentia

l fo r th e discharg e to violat

e th e cold wate

r protectio n rul e (OA

R340-041-0028( 1 l)(b) . Th e Departmen

t als o evaluated th e therma

l plum e i n accordanc e wit

h OA R340-041-005 3 (2)(d) . No permi t limit s fo r temperatur

e ar e needed betwee

n Novembe

r 1 an d March 3 1 or

fo r th e therma

l plume . Bacteria Th e Department' s 303(d) Lis t indicate s th e Willamett

e Rive r i s wate r qualit y limited fo

r bacteri aduring fall , winte r an d spring . Th

e 200 6 Willamett

e TMD L deal s wit

h bacteri aissues . Th

e TMD L state s ther

e i s currently a n "exces s bacteria

l load " to th e Willamett

e Rive r an d wastewate

r treatmen t plant s ar e allocated permitted effluen t limit s a t the bacteri astandard . Whe n operating properly , thes e discharge s will no t caus e o r contribut e to wate r qualit y violation s an

d are arelatively smal

l proportio n of

the tota l loading t o the Willamett

e River . Th e Cit y o f Corvalli s i s i

n ful l complianc e wit

h th e Willamett

e TMD L i n regard s to bacteria . Dissolved Oxygen Th e mainste

mWillamett

e Rive r i s wate r qualit y limited fo

r dissolved oxyge

n during the spawnin

g season (Octobe r 1 5 throug h Ma y 15 ) fro mriver mil e 14 9 throug h rive r mil e 50 . No TMD

L ha s bee n written to addres s th e Willamett

e Rive r dissolved oxyge

n listin g an

d therefor e n o WL A fo r oxyge n demandin

g pollutant s have bee n assigned t

o the Cit y of Corvallis . Th

e permi t wil l includ

e aclaus e allowin g th e Departmen t to reope n th e permit an d includ e adissolved oxyge

n WL A whe n aTMD L ha s bee n written an

d approved . OpCertClassWorkshee t

(Rev . 12/03/2008 )Cit y o f

Corvalli s Evaluatio n Repor t Pag e 8 Mercury Th e Department' s 303(d ) Lis t indicate s th e Willamett e Rive r i s wate r qualit y limite d fo r

mercur y becaus e o f exces s concentration s foun d i n fish tissues . Th e Departmen t i s proposin g t o perfor

mth e TMD L i n atwo-phase d approach . Th e firs t

phas e ha s bee n complete d an d ha s receive d EP A approval . Th e first phas e o f th e TMD L lay s ou t an implementatio n strateg y t o gai n abette r understandin g o f

th e fate an d transpor t

o f mercur y i n th e Willamett e Basin . Th e implementatio n strateg y require s certai n poin t source s (includin g Corvallis ) t o conduc t monitorin g for

mercury an d methylmercury an d t o submi t aMercur y Minimizatio n Pla n i f asourc e i s foun d t o b e asignifican t

contributo r

o f mercury . Thi s permi t

require s th e facility t o monito r fo r tota l an d dissolve d mercury an d methylmercury twic e pe r year usin g EP A Metho d 163 1 E . Tota l an d dissolve d mercur y mus t achiev e adetectio n limi t

o f 0.07 3 ng/L an d tota l an d dissolve d methylmercury mus t achiev e adetectio n limi t o f 0.0059 9 ng/

L unles s otherwis e approve d i n writin g b y th e Department . Th e permitte e ma y reques t th e mercur y monitorin g b e eliminate d after tw o year s o f

monitorin g i f

th e Departmen t

i s satisfie d with th e result s o f th e data . I f ther e i s wid e variabilit y withi n th e results , th e Departmen t may requir e additiona l monitoring . Th e City o f

Corvalli s ha s implemente d amercur y reductio n pla n tha t include s workin g with dentist s t o minimiz e mercur y wast e throug h th e us e o f amalgamseparators , mercur y permi t limit s for significan t

industria l users , an d mercur y collectio n program s domesticall y an d throug h th e schools . T o date , mercury hea d work s loadin g ha s bee n reduce d b y approximatel y 97 % throug h th e mercur y reductio n pla n effort . Mixin g Zon e Analysi s Federa l regulation s (4 0 CF R131.13 ) allo w fo r th e us e o f

mixin g zones , als o know n a s "allocate d impac t zones" . Whe n usin g mixin g zone s acut e toxicit y t o driftin g organism s mus t b e prevente d an d th e integrit y o f th e waterbod y a s awhol e may no t b e impaired . Mixin g zone s allo w th e initia l mixin g o f treate d wastewate r

an d receivin g water , bu t

ar e no t designe d t o allo w fo r

treatment . EP A doe s no t hav e specifi c regulation s pertainin g t o mixin g zones . Eac h stat e mus t adop t it s ow n mixin g zon e regulation s tha t ar e subjec t

t o revie w an d approval b y EPA . I n State s tha t

lac k approve d mixin g zon e regulations , ambien t wate r qualit y standard s mus t

b e me t a t th e en d o f th e pipe . Th e Departmen t

ha s adopte d th e two-numbe r aquati c lif

e criteri aan d develope d mixin g zon e regulation s wit h respec t t o that . Th e regulation s are primaril y narrativ e an d essentiall y requir e th e permi t write r t o us e bes t professiona l judgmen t

i n establishin g th e siz e o f th e mixin g zone . Base d o n EP A guidanc e an d th e Department' s mixin g zon e regulations , tw o mixin g zone s ma y b e develope d for eac h discharg e tha t

reflec t acut e an d chroni c effects : 1 ) Th e acut e mixin g zone , als o know n a s th e "zon e o f initia l dilution " (ZID), an d 2 ) th e chroni c mixin g zone , usuall y referre d t o a s "th e mixin g zone" . Th e acut e mixin g zon e i s designe d t o preven t lethalit y t o organism s passin g throug h th e ZID . Th e chroni c mixin g zon e i s designe d t o protec t th e integrity o f th e entir e wate r

bod y a s awhole . Th e allowabl e siz e o f th e mixin g zon e shoul d b e base d upo n th e relativ e siz e o f th e discharg e t o th e receivin g stream , th e beneficia l use s o f th e receivin g stream , locatio n o f othe r discharge s t o th e sam e wate r

body , locatio n o f

drinkin g wate r

intakes , an d othe r

considerations . Mor e specifi c guidanc e i s availabl e fro

mEP A regardin g criteri ause d i n appropriatel y sizin g aZID . Primaril y th e ZI D mus t b e designe d t o preven t lethalit y t o driftin g organisms . Th e Department' s mixin g zon e regulation s stat e th e mixin g zon e mus t b e les s tha n th e tota l strea mwidth a s necessai y t o allo w passag e offis h an d othe r aquati c organisms . Earl y recommendation s regardin g th e siz e o f th e zon e o f passag e originate d fro mth e Departmen t o f Interio r (1968) . The y recommende d azon e o f passag e o f

7 5 percen t o f th e cross-sectiona l are aand/o r volum e o f

flow o f th e receivin g stream . Base d o n thi s recommendation , th e Department' s standar d practic e i s t o allo w n o mor e than 2 5 percen t o f th e strea mflow for mixin g zones . Th e curren t

permi t provide s for

amixin g zon e fo r

Outfal l 00 1 tha

t consist s o f

tha t portio n o f

th e Willamett e Rive r containe d withi n aban d extendin g ou t fro mth e wes t

ban k thirty (30 ) fee t

beyon d th e easter n edg e o f th e diffuser an d extendin g fro mapoin t te n (10 ) fee t

upstrea man d thre e hundre d (300 ) fee t downstrea mfromth e OpCertClassWorkshee

t (Rev . 12/03/2008 )Cit

y o f Corvalli s Evaluatio n Report Pag e 9 diffuser . Th e Zon

e of Immediat e Dilutio n (ZID ) i s define

d a s tha t portion of th e allowabl e mixing zone tha t i s within thirt

y (30 ) fee t of the poin t of discharge . Th

e Departmen

t propose s to retai n th e existin g mixing zone . Th e existin g permi

t include s Outfal

l 002 i n th e sectio n wit

h th e above mixing zon

e bu t th e Dixon Cree

k discharg e doe s no t

occu r within th e defined area . Th e Departmen t i s not proposing to defin

e amixing zon

e fo r Outfal l 002 a t thi s time . Give

n th e intermitten

t natur e o f th e discharg e a

t Outfal l 002 an d th e fac t tha t i t i s onl y used during ver

y hig h rive r flow periods , i t

i s no t expected tha

t th e discharg e wil l caus e or contribut e to wate r qualit y standar d violations . Finally , th e Departmen

t evaluated th e therma

l plum e i n accordanc e wit

h OA R340-041-005 3 (2)(d) t

o ensur e th e discharg e doe s no

t caus e advers e effect

s to salmonid s a s described below : Impairmen t o f a n activ e salmonid spawning are awher e spawnin g redd s ar e located o r likely to be located i s prevente d o

r minimize d b y limiting potentia

l fish exposur

e t o temperature s o f

13° C o r mor e fo r salmon an d steelhead , an

d 9° C fo r bull trout . According to th e Oregon Departmen t of Fis h an d Wildlif e (ODF&W

) distric t biologist , thi s requiremen

t i s me t becaus e bull trou t

ar e no t adesignated beneficia

l us e of th e mai n ste m Willamett e Rive r an d ther e ar e n o know n activ e salmon spawnin

g redd s fo r Fal l o r Spring Chinoo

k within thi s are ao f th e river . Acut e impairmen

t o r instantaneou s lethalit

y i s prevente d or

minimized b

y limitin g potentia

l fish exposur

e t o temperature s o f

32° C o r mor e to les s tha

n 2 seconds . Thi s requiremen t i s me t becaus e th e maximu

mdischarg e temperatur e i s les s tha

n 32°C . Therma l shoc k i s prevented or

minimized b y limitin g potentia l fish exposur

e to temperature s of

25° C o r mor e to les s tha n five percen

t o f the cros s section of

the wate r body . Thi s requiremen

t i s me t becaus e th e maximu

m discharg e temperatur

e i s les s tha

n 25°C . Migration blockag e i s prevented o r minimized b

y limitin g potentia

l fish exposur

e t o temperature s of

21° C o r mor e to les s tha

n 2 5 percen t of th e cros s sectio n o f

th e wate r body . According to th e temperatur e dat aa t USG S Gage No . 1416650

0 sinc e 2001 , the 99t

h percentil e o f

th e running 7-da

y averag e maximu

minstrea m temperatur e i s 20.8°C . Using wors t

cas e condition s (25 % of

367 0 cf s 7Q1 0 strea

mflo w a t 20.8° C an d th e discharg e flo

w of 9. 7 MG D o r 15. 0 cf s a t 22.9°C) , th e mixe

d temperatur

e ca n b e calculated . Th e mixe d temperatur

e i s calculated usin g dilutio n based o n effluen t flow an d receivin g strea

mflow, an d using effluen t temperatur

e an d backgroun

d temperature , a s follows : Dilutio n = (Effluen

t flow + 25 % o

f Rive r flow) = H5. 0 cf

s + (367 0 cf

s x 0.25V ) = 62. 2 Effluen t flow 15. 0 cf s Mixe d Temp . = (Effluen

t temp . - Rive

r temp. t + Rive r temp . = (22.9 o C-20.8°C 1 + 20.8° C = 20.83° C Dilution 62. 2 Th e mixe d temperatur

e i s 20.83° C an

d the final therma

l plum e requiremen

t i s satisfied . 

### PERMI T HISTOR Y Previou s Permi tActio n Th e Departmen

t issue d NPDE S Permi t #10171 4 o

n August 9,1999 . Th

e permi t expire d o n June 30,2004 . Th

e Departmen t received renewa

l applicatio n #98379 3 o

n Decembe

r 31,2003 . Th

e permi t shall no t be deeme d t o expir e until final actio

n has bee n take n o n the renewa

l application . OpCertClassWorkshee t

(Rev . 12/03/2008 )Cit

y o f Corvalli s Evaluatio n Report Pag e 1 0 Tw o treated effluen

t outfalls , fiv

e combine d sewe r overflo w points , fou

r emergenc y sanitar y sewe r overflo w points , atreate d combine

d sewe r effluen t outfal l an d agroundwate

r lagoo n outfal l poin t ar e identifie d i n th e 199 9 permit . Curren tPermi tLimit s Schedule A contain s th e effluen t limit s fo r th e treatmen

t facility . Som

e limit s ar e dependen

t upo n th e season (summe r an d winter ) whil e other s ar

e year-round . Th

e curren t permit limit s ar e a s follows : Outfall s 00 1 an

d 002 - Wastewate

r Treatmen t Plan t Discharg e (1 ) Ma

y 1-Octobe r

31 :

. Paramete r CBOD 5 TS S Averag e Effluen t Concentration s Monthly Weekl

y 1 0 mg/ L 1 5 mg/

L 1 0 mg/ L 1 5 mg/

L Monthly Averag e lb/da y 81 0 81 0 Weekl

y Averag e lb/da y 120 0 120 0 Dail

y Maximu m lb s 160 0 160 0 (2 ) November!-Apri l 30 :

Paramete r CBOD 5 TS S Averag e Effluen t Concentration s Monthly Weekl

y 2 5 mg/ L 40 mg/

L 3 0 mg/ L 4 5 mg/

L Monthl

y Averag e lb/da y 350 0 4300 Weekl

y Averag e lb/da y 570 0 640 0 Daily Maximu m lb s 700 0 860 0 (3 ) Othe

r Parameters : Othe r parameter s (year-round) E. coli Bacteri a pH CBOD 5 an d TS S Remova

l Efficiency Tota l Chlorin e Residua l Limitation s

Shal l not excee d 12 6 organisms pe

r 10 0 m l monthl y geometri c mean . No single sampl

e shal l excee d 40 6 organisms pe

r 10 0 ml . (Se e Not e 1 ) Shal l no t be outsid e th e rang e of

6. 0 - 9. 0 fo

r mor e tha n a tota l of 7 hours an d 2 6 minute s i

n an y calenda r month , an d n o individua

l excursion fromthi s range shal l excee d 6 0 minute s Shal l no t b e les s tha n 85 % monthl

y average , excep

t whe n flows excee

d 1 2 MG D monthl y average , the percen

t remova l efficienc y shal l no t b e les s tha n 75 % monthl

y average Shal l not excee d adail y averag e concentratio

n of 0. 5 mg/ L

OpCertClassWorkshee t

(Rev . 12/03/2008 )Cit

y o f Corvalli s Evaluatio n Repor t Pag e 1 1 NOTES : 1 . I f asingl e sample exceed s 40 6 organism s pe r 10 0 ml , then five consecutiv e re-sample s ma y b e take n a t fou r hour interval s beginning within 2 8 hour s afte r the origina

l sample was taken . I f

the lo g mea

n of th e five re-sample s i s les s tha

n o r equa l to 126 organism s pe

r 10 0 ml , aviolatio n shal l no t

b e triggered . Operationa

l an d maintenanc e requirements , discharg e prohibition s an d othe r condition s ar

e included fo

r th e othe r outfalls . Complianc e Histor y Th e facilit y wa s las t inspected o

n June 21,201 0 an

d wa s foun d to b e operatin g i

n complianc e wit

h the permit . Th e followin g Notice s of

Noncomplianc e (NON

) have bee n issued fo r violation s documente

d a t thi s facilit y i n th e las t five years : 

### Dat e o f Violatio n April 29 , 200 8 Typ e o f Enforcemen

t Actio n Warning Lette

r Descriptio n o f Violatio n , . Incomplet e Discharg e Monitoring Repor t TYPE S O F PERMI T LIMITATION S Two categorie s o f

effluen t limitation s exis t

fo r NPDE S permits : 1 ) Technology base d effluen t limits , an d 2 ) Wate r qualit y based effluen

t limits . Technology based effluen t limit s have bee

n established b

y EP A rules . Technology based effluen

t limit s wer

e establishe d t

o requir e aminimu

mleve l of treatmen t fo r industria l o r municipa l source s usin g availabl e technology . Wate r qualit y base d effluen t limit s ar e designed to be protectiv e of th e beneficia

l use s o f th e receivin g wate

r an d ar e independen

t o f th e availabl e treatmen

t technology . I n addition , whe

n performin

g apermit renewal , ther

e ar e existin g permit

limit s (discussed above) . Thes e ma y b e technology-based limits , wate r quality-based limits , o

r limit s base

d o n bes t professiona

l judgment . Whe

n renewing apermit , th e mos t stringen t o f technology-based , wate

r quality-based , an

d existin g effluen

t limit s mus t b e applied . Technology-Base d Effluen tLimit s EP A ha s establishe d secondai y treatmen t standard s fo

r domesti c wastewate

r treatmen t facilities . Th

e standard s ar e foun d i n 40 CF RPar t 133 . Thi s facilit

y mus t achiev e abiochemica

l oxyge n deman d (BOD 5 ) monthl

y averag e o f 3 0 mg/ L an d aweekly averag e o

f 4 5 mg/ L o r acarbonaceou s biochemica l oxyge n deman d (CBOD 5 ) monthl y averag e of

2 5 mg/ L an d aweekl y averag e o

f 40 mg/L . Th e facilit

y mus t als o achiev e asuspended solid s (TSS ) monthl

y averag e of

3 0 mg/ L an d aweekl y averag e o f

4 5 mg/L . Th

e p H mus t b e betwee n 6. 0 an d 9.0 . I n addition , aminimu

mleve l o f percen t remova l fo r BODS an d TS S fo r municipa l discharger s i s require d b

y th e Cod e of Federa l Regulation s (CFR

) secondaiy treatmen

t standard s (4 0 CFR , Par

t 133) . A n 8 5 percen

t remova l efficienc y limit i s generally included i

n permit s i n orde r to compl y wit h federa l requirements . However , federa

l regulation s include specia l consideration s fo

r facilitie s wit

h combine d sewers . 4 0 CF

R 133.10 3 (a ) state s tha

t "For such treatmen

t works , th e decisio n mus t

b e mad e o n acase-by-cas e basi s a

s to whethe r an y attainabl e percentag e remova l leve l ca n b e defined , an

d i f so , wha t th e leve l shoul d be. " Previously , th e Departmen

t determined th e facilit

y shoul d b e capabl e of

achieving a75 % remova

l efficienc y whe n monthl y averag e flows excee

d 1 2 MGD . Th

e facilit y ha s bee n able t o compl y wit h thi s limi t an d th e Departmen t propose s t o retai n th e limit . OpCertClassWorkshee t

(Rev . 12/03/2008 )Cit

y o f Corvalli s Evaluatio n Report Pag e 1 2 Orego n Administrativ e Rule s als o establis h minimu mdesig n criteri afo

r domesti c treatmen

t facilities . I

n th e Willamett e Basin , th e CBOD5 an

d TS S minimu

mdesig n criteri ai s 1 0 mg/

L a s amonthl

y averag e i n th e summe

r perio d an d secondai y treatmen t i n th e winte

r period . I n addition , ther

e ar e requirement s fo

r disinfection an

d reductio n of

oxyge n demandin

g pollutants . Wate r Quality-Base d Effluen tLimit s Pollutan t parameters shoul

d b e limited if

ther e i s areasonable potentia

l fo r th e discharg e to caus e o

r contribut e to a n excursion abov

e an y stat e wate r qualit y criteri ao r standard . I

n addition , TMDL s ma

y assign WLAs to source s to addres s in-strea

mviolation s o

f wate r qualit y criteria . Th e Departmen

t i s required to determine whethe r th e discharg e ha s th e reasonabl e potentia l to caus e o

r contribut e t o a n exceedenc e o f

awate r qualit y criterion . EP

A ha s developed ametho d t o mak e thi s determinatio n fo

r toxi c pollutant s calle d areasonabl e potentia l analysi s (RPA) . A

n RP A relie s o n statistica l probabilit y to determin

e th e likelihoo d tha

t adischarg e wil l violat

e a n instrea mcriterio n base

d o n the effluen

t data , it s variability , availabl e dilution , an d th e receivin g wate

r backgroun

d concentration . Th

e Departmen

t ha s developed RP

A spreadsheet s tha

t emplo y EPA' s methodology . A reasonabl e potentia

l analysi s (RPA

) fo r ammonia, chlorine , cyanid

e an d metal s an

d toxi c organic s wa s performe d b y evaluating effluen

t dat ai n th e DE Q spreadsheets . Th e RP A fo r ammonia(se e Attachment#2 ) indicated tha t ther e i s n o reasonabl e potentia

l to caus e o

r contribut e to a n excursion of

th e stat e wate r qualit y criteri aduring the summe r (low-flow) , or

winte r (high-flow ) season whic h include s the salmoni

d rearin g (Oc

t 15-Mayl5 ) an

d migration season s (Ma

y 16-Oc t 14) . Th e analysi s fo

r ammoniaconsidered representativ e pH , temperature , an d alkalinit y condition s i

n bot h th e treate d effluen

t an d receivin g wate

r upstrea mfro mth e outfal

l to determin

e appropriat

e ammoniacriteri aaccording th e state' s rules . Effluen t ammoniadat

afro mth e pas t thre e years , a s well a s backgroun d ammoniafro

m198 7 to 200 4 fro mjus t upstrea mo f th e outfall , wer

e als o use d i n th e analysis . No ammonialimit s wil l be proposed . Th e RP A fo r metal s indicated tha

t there i s n o reasonabl e potentia

l to exceed bot

h th e corresponding stat

e aquati c (se e Attachmen

t#3),an d huma n healt h (se e Attachmen t

#4) wate r qualit y standard s fo

r thes e pollutants . Effluen t dat aderive d usin g acceptabl e reportin g limit s fro m2003-2009 wa s used i

n th e analysis . Backgroun

d metal s dat acollected fro

m2002-200 3 one-half

mile upstrea

mfro mth e outfall wa s als o used . Critica l lo w Willamett

e Rive r flows fo r al l toxi c analyse s wer

e derive d fro maDFLO

W model . Th

e ra w receivin g wate

r dat ase t included combine

d flows fro mth e Willamett

e Rive r measured a

t Harrisburg , an

d the Long To mRive r befor e th e confluenc e wit

h th e Willamett

e an d the Maiy s River . Dat

afro m196 9 throug h 200 4 wa s used . Whole Effluent

Toxicity Whole Effluen

t Toxicit y (WET) i s ater

mused to describ e the aggregat e toxi c effec

t of a n aqueou s sampl

e (e.g. , whole effluen

t wastewate

r discharge ) a s measure

d b y a n organism' s respons e upo

n exposur e t o th e sampl

e (e.g. , lethality , impaire

d growt h or reproduction) . WE

T test s replicate , to the greates t exten t possible , the tota

l effec t an d actua l environmenta

l exposur e o f aquati c lif e t o toxi c pollutant s i

n a n effluen t without requiring the identification o f

the specific pollutants . WE T testin g i s avita

l componen

t o f the wate r qualit y standard s implementation throug

h the NPDE S permittin g process . EPA' s WE T tes t method s include a

n acut e tes t (9 6 hours o

r less , endpoint : mortality) , an d achroni c tes t

( 7 da y life-cycle test , endpoints : growth , reproduction , an d mortality) . EP

A ha s developed WE

T tes t protocol s using bot h freshwate

r an d marine an

d estuarin e tes t

species . EP

A recommend s running test s using a n invertebrate , vertebrat e an d aplan t to identif y th e mos t sensitiv e specie s fo

r developin g NPDE S WE

T permi t limits o r testin g requirements . Th

e organisms used i

n freshwate

r WE T test s ar e Ceriodaphm

adubi a(freshwate

r flea), OpCertClassWorkshee t

(Rev . 12/03/2008 )Cit

y o f Corvalli s Evaluatio n Repor t Pag e 1 3 Pimephale s promela s (fathea d minnow ) an

d Raphidoceli s subcapitata(gree n alg aformerl

y know n a s Selanastru mcapricornutum) . Thes e organism s ar e indicator s o

r surrogate s fo

r th e aquati c communit

y to b e protected , an

d ameasur

e of th e rea l biologica l impact fro mexposur e to th e toxi c pollutants . To protect wate r quality , EP

A recommend s tha

t WE T test s b e used i

n NPDES permit s togethe

r wit h requirement s base

d o n chemical-specifi c wate

r qualit y criteria . WE T test s ar e designed to predic t

th e impact

an d toxicit y of effluents discharged fro

mpoint source s int

o water s o f th e United States . WE

T monitoring requirement s ar e included i

n NPDE S permit s to generat e dat afo r us e i n assessing whethe

r the effluen

t a s awhole demonstrate s toxicity . Th e test s ar e use d to determine th e percentag e of effluen t tha t produce s a

n advers e effec

t o n agrou p of tes t organisms . Th

e measured effec

t ma y b e fertilization , growth , reproduction , o r survival . A

n acut e WE T tes t i s considered t o show toxicit y if lethalit y i s foun d a t concentration s les s tha

n thos e occurring a

t th e edg e of

th e zon e of immediat e dilutio n (ZID) . A chroni c WE T tes t i s considered to sho

w toxicit y if an y advers e affec

t occur s a t concentration s les s tha

n tha t whic h i s know n t o occu r a t the edg e of

th e mixin g zone . Th e Cit y wa s require d to conduct

acut e an d chroni c WE

T test s quarterly fo

r on e yea r wit h n o furthe r testin g i f test s resulte d i

n n o toxicit

y a t th e determined dilutions . Th e Departmen

t ha s reviewed th e report s an d foun d tha t all result s of

th e test s passed all acut

e an d chroni c toxicit

y requirements . Th

e proposed permi

t wil l requir

e tha t acut e an d chroni c WE

T test s b e performe

d quarterly fo

r on e yea r or annuall y fo r fou r year s durin g the permit cycle . PERMI T DRAF T DISCUSSIO N A n Antidegradatio n Revie

w wa s completed (se e Attachmen t#5 ) wit h arecommendation to procee d wit h thi s permi t action . Th

e proposed permi

t limit s an d condition s ar

e described below . Refe

r t o th e proposed permi

t an d the discussio n above whe

n reviewing thi s section . Fac e Pag e Th e face pag e provide s information abou t th e permittee , description of th e wastewater , outfal

l locations , receivin g strea

minformation , permit

approva l authority , an

d adescription of

permitted activities . Th

e permitte e i s authorize d t o construct , install , modify , o r operat e awastewate

r collection , treatment , contro l an d disposa l system . Permit s discharg e of treate d effluen

t to the Willamett

e Rive r an d to beneficiall

y lan d appl y treated Clas s A , Clas s B , Clas s C , an d Clas s D recycle d wastewate r within limit s se

t b y Schedule A an

d th e followin

g schedules . Al l othe

r discharge s ar

e prohibited . h i accordanc e wit

h OA R340 , Division 4

9 all permitte d municipa

l wastewate

r collectio n an

d treatmen t facilitie s ar e to receiv e aclassification based o n the siz e an

d complexit

y o f th e systems . Th

e Departmen

t ha s incorporate

d th e classificatio n of

the collectio n an

d treatmen t system s int

o the NPDES discharg e permit . Th e Departmen

t evaluated the classification s fo r th e treatmen

t an d collectio n system s (see Attachmen t#6) . Th e Departmen

t i s no t proposing an

y change s t

o th e syste mclassification s fo

r th e facilities . Schedul e A - Wast e Discharg e limitation s Schedule A contain s th e effluen t limitation s propose d fo

r Outfall s 00 1 an

d 002 . Ther

e ar e requirement s an

d condition s fo

r discharge s fro

mth e combine

d sewag e overflow treatmen t facility , Outfal

l 012 , Finally , Schedule A prohibit s advers e impacts o n existin g o

r potentia l beneficia l use s o f groundwater . Outfall s 00 1 an

d 00 2 - Treate d Effluen

t Th e Departmen

t i s generall y proposing t

o retai n th e existin g limits . Ne w limit s ar e propose d fo

r therma l discharge s whil e mor

e stringen t limit s ar e proposed fo

r tota l residua l chlorine . CBOD 5and

TSS concentration and

mass limits OpCertClassWorkshee t

(Rev . 12/03/2008 )Cit

y o f Corvalli s Evaluatio n Report Pag e 1 4 Based o n th e Willamett

e Basin minimu

mdesign criteria , wastewate r treatmen t resultin g i n amonthl y averag e effluen t concentratio n o f

1 0 mg/ L fo r CBOD 5 an

d TS S mus t

be provided fro

mMa y 1 throug h Octobe r 31 . From Novembe r 1 through Apri l 30 , aminimu mof secondar y treatmen t i s required . Secondaiy treatmen t i n Orego n i s defined a s monthl

y averag e concentratio n limi t o f 3 0 mg/ L fo r BOD 5 o r 2 5 mg/ L fo r CBOD 5 an

d 3 0 mg/ L fo r TSS . Th e Cit y ha s previousl

y requeste d concentratio n an d mas s limit s base

d o n CBOD 5 . Th

e Departmen

t i s proposing to rene

w th e existin g concentratio n limit s tha t ar e a t leas t a s stringen

t a s th e basin minimu

mdesign criteria . Th

e proposed monthl

y averag e summe

r CBOD

5 an d TS S concentratio n limit s ar e 1 0 mg/ L wit h a weekl y averag e limi

t o f 1 5 mg/L . Th

e propose d monthl

y averag e winte

r CBOD 5 concentratio n limit s ar e 2 5 mg/ L wit h aweekl y averag e limit

of 40 mg/L . Th e summe r monthl y averag e mas s load s ar

e based o n the averag e dt

y weathe r design flo w (9. 7 MGD ) an

d a concentratio n of

1 0 mg/L . Th

e weekl y averag e an

d dail y maximu mmas s limit s wer

e 1. 5 an d 2. 0 time s th e monthl y averag e mas s limits , respectively . Th e calculation s fo

r th e proposed summe

r limit s are : a ) 9. 7 MG D x 8.3 4 lbs/ga

l x 1 0 mg/ L = 80 9 (810 ) lbs/da

y monthl y avg . b ) 80 9 lbs/da

y monthl y avg x 1. 5 = 121 4 (1200 ) lbs/da

y weekl y avg . c ) 80 9 lbs/da y monthl y avg x 2 = 161 8 (1600 ) lb s daily maximu m Th e winte r CBOD

5 an d TS S monthl

y averag e mas s limit s wer

e base d o n th e averag e we

t weathe r design flo w t o th e facilit y equaling 17. 0 MG

D an d monthl y averag e concentration s of 2 5 an d 3 0 mg/1 , respectively . Th e weekl y averag e an

d daily maximu

mmas s limit s wer

e 1. 5 an d 2. 0 time s th e monthl

y averag e mas s limits , respectively . Th

e calculation s fo

r th e proposed CBOD 5 winte r limit s are : a ) 1 7 MG D x 8.3 4 lbs/ga

l x 2 5 mg/ L = 3545 (3500 ) lbs/da

y monthl y avg . b ) 354 5 lbs/da

y monthl y av g x 1. 5 = 531 8 (5300 ) lbs/da

y weekl y avg . c ) 354 5 lbs/da

y monthl y avg x 2 = 709 0 (7100 ) lb s daily maximu m Th e previou s tw o permit

action s included aweekl

y averag e CBOD 5 limit

of 570 0 pound s pe

r day . Thi s limit was calculate d base

d o n the weekl

y concentratio n limit

of 4 0 mg/ L time s 1 7 MG

D time s 8.3 4 lbs/ga

l an d not 1. 5 time s th e monthl

y averag e i

n lbs/da y a s indicated i

n th e calculatio n above . Thi s limi t was agreed upo

n during th e origina l desig n o f th e existin g facility , Therefore , th e Departmen t propose s to retai n th e previou s permit s weekl y averag e limi

t of 570 0 pound s pe

r da y h i addition ; th e dail

y maximu mlimi t calculatio n indicate s th e limit should have bee

n 710 0 pound s pe

r day . However , the previou s permit limited th e dail

y maximu mt o 7000 pound s pe r da y an d the Cit y ha s bee n abl e to compl

y wit h th e ol d limit . Th

e Departmen

t camio t rais e th e limit , therefor e the existin g limi

t o f 700 0 pound s pe

r da y wil l b e retained . Th e calculation s fo

r th e propose d TS S winte

r limit s are : a ) 1 7 MG D x 8.3 4 lbs/ga

l x 3 0 mg/ L - 425 3 (4300 rounded ) lbs/da y monthl y avg . b ) 425 3 lbs/da

y monthl y avg x 1. 5 ^ 638 0 (6400 rounded) lbs/da y weekl y avg . c ) 425 3 lbs/da

y monthl y av g x 2 ~ 8506 (8600 rounded) lb s daily maximu m CBOD and

TSS Percent Removal Efficiency A minimu mleve l o f 85 percen t remova l efficienc y fo r CBOD 5 an

d TS S fo r municipa l discharger s i s normall

y require d b y the Cod e o f Federa l Regulation s (CFR

) secondaiy treatmen

t standard s (4 0 CFR, Par

t 133.102) . However , federa

l regulation s includ

e specia l consideration s fo

r combine d sewers . 40 CF

R133.103(a

) state s such treatmen

t works ma y not b e capable of

meeting th e percen

t remova l requirement s during we

t weather . Fo

r such treatmen

t works , th e decisio n must

be mad e o n acase-by-cas e basi s a s t

o whethe r an y attainabl e percentag e remova l leve l ca n b e defined , an

d i f so , wha t the leve l shoul d be . OpCertClassWorkshee t

(Rev . 12/03/2008 )Cit

y o f Corvalli s Evaluatio n Repor t Pag e 1 5 Th e prior permit require d th e facilit

y to achieve 85 percen

t remova l efficienc y a s amonthl

y averag e except whe n flow s excee

d 1 2 MG D a s amonthl

y average . Whe

n flow s exceed 1 2 MGD , th e percen t remova l efficienc y ma y not b e les s tha

n 7 5 percen

t monthl y average . Th

e Departmen

t propose s to retain th e existin g limits . Arsenic Arseni c i s foun

d a t naturally occurrin g elevated concentration s i n man y of the stream s i

n Oregon , includin g th e Willamett e River . Muc

h of th e Cit y of Corvallis' s drinking wate

r i s take n fro mth e Willamett

e Rive r wher e th e tota l arseni c concentration s hav e bee n measure d a t approximatel

y 0.46 6 ug/L , Th

e tota l arseni c concentratio n i

n th e wastewate

r facility' s effluen

t wa s measure

d a t 1. 3 ug/L . Th e Departmen

t i s currently i

n th e proces s of

revisin g it s huma

n healt h arseni c criterio n an

d wil l b e proposin g a criterio n t o bette

r reflec t th e mor e toxi c speciation' s o f

arseni c (inorgani c arsenic ) usin g aregionally appropriat e health-ris k calculatio n method . Thi s wil l result i n ashif t of th e standar

d fro m"total " to the "inorganic " fraction , an d re-evaluatio n to bette

r reflec t regiona l healt h risks . Give

n thes e imminen

t changes , the facilit

y i s bein g directe d to ensur

e tha t current treatmen t facilitie s ar

e being operate d a

t th e highes t

an d bes t exten t practicabl e an d tha t they implemen

t a n interi mmonitoring an

d sourc e contro l strateg y t o collect th e necessaiy dat

at o implemen t th e ne w standar d durin g th e nex

t permi t cycle . Th e minimu msafeguard s ar

e discussed below : Th e facilit y ha s conducted apreliminar y sourc e investigatio n o f

al l industria

l user s t o ensur e tha t n o permitte d significan t industria l user s discharg e proces s wastewater s tha t contain arseni c a s aproces s byproduct . Ther e ar e n o federall y mandated technology-base d effluen t limit s fo r arseni c fo r an y o f th e industria

l user s i n th e system . Ther e ar e n o aquati c toxicit

y criterio n fo

r tota l arseni c an

d discharge s ar

e well below th e aquati c toxicit y criteri a fo r Arseni c I H (190/36 0 ug/L) . Th

e activated sludg e treatmen

t proces s effectivel

y remove s som

e sedimentbase d arseni c an

d incorporate s asmal

l percentag e of

dissolve d arseni c i n th e sludge . Th e Departmen

t ha s established aquarterly averag e o f 2. 5 ug/ L tota l arseni c a s anon-regulator

y benchmar

k to us e i n assessin g whethe r th e applicabl e treatmen

t technology i s providing th e highes t an d bes t practicabl e treatmen

t fo r arseni c i n th e discharge . Thi s quarterly averag e valu e i s the Calculate d Maximu mEffluen t Concentration an

d reflect s a wors t cas e scenario , usin g historica l discharg e an

d ambien t dataa t th e 95 % confidence level . For th e purpose s of th e Departments ' arseni c interimimplementation procedur e an d thi s permit , the curren

t treatmen t facilit y wil l b e considered th e "Bes t

Availabl e Treatment " an

d th e requiremen

t fo r th e facilit y to continu e t

o operat e an d manag e treatmen

t a t th e "highes t

an d bes t exten t practicable " i s i n th e propose d permit . A s aperformanc e measure , if

th e quarterly averag e concentration s of tota l arseni c excee d 2.5ug/L , the facilit y wil l b e require d to submi t arepor t to th e Departmen

t detailing the condition s tha t lea d to th e exceedence . Th

e Departmen

t wil l us e th e report , monitoring information an d operation record s to determin e if th e facilit y failed to compl

y wit h th e narrativ e operationa

l requirements . Th e "monitoring strategy " wil l requir e tha t the facilit y perfor mth e following steps :

• Th e permi t wil l includ

e th e requirement s (i n Schedule D ) fo r th e facilit y to develo

p an d submi t fo r approval , withi n 12

0 day s of permi t issuance , a

n additiona

l Arseni c Quantificatio

n Plan . A t aminimum , th e pla n wil l referenc e th e Schedul e B an d Pretreatmen

t monitorin g requirement s i

n th e permit . Th e permitte e mus t

begi n implementation o

f th e Arseni c Quantificatio n Pla n within two week s of notification o f

pla n approva l b y th e Department . I f

th e Departmen

t determine s tha

t th e pla n i s no t approvable , th e Departmen

t will notif y th e permitte e o f

th e missin g pla

n elements . Th

e permitte e i s require d t o implemen

t th e pla n unti l written notificatio n b y th e Departmen

t tha t furthe r implementatio n i s not warranted . • Th e permit wil l requir

e tha t the facilit y begi n implementatio n o f

th e approve

d pla n within tw o week s of Departmenta

l approval . • Upo n approva l of th e revise d inorganic arseni c criterion , th e Departmen t intend s t o confe r wit h th e facilit y wit h th e purpos e of

evaluating the collecte d Schedul e B an d Pretreatmen

t monitoring datato determine if

there migh

t b e a n affirmativ

e o r negativ e Reasonabl e Potentia l Analysi s (RPA) finding fo r the inorgani c arseni c criterion . OpCertClassWorkshee t

(Rev . 12/03/2008 )Cit

y o f Corvalli s Evaluatio n Report Pag e 1 6

• Upo n approva l of the revised inorgani c arseni c criterion , if th e collecte d Schedule B an d Pretreatmen

t monitoring dat

aindicate s the potentia

l fo r a n affirmativ

e RP A finding , th e Departmen

t expect s th e facilit y t o develo p amanagemen

t strateg y t o ensur e compliance . Th

e facilit y would have th e remainde

r of th e permi t cycle t o collec t an y additiona

l dat ato suppor t th e managemen

t strateg y an

d undertak e an y require d administrativ e action s (i. e variance , site-specifi c criterion , complianc e schedule , permit s modification , etc.) . • Upo n approva

l o f th e revise d inorgani c arseni c criterion , if th e collecte d Schedule B an d Pretreatmen

t monitoring dat

aindicate s anegativ e RP

A finding, th e facilit

y ma y conclud e an y monitoring o

r complianc e requirement s t

o addres s th e narrativ e arseni c effluen t limit s o r benchmarks bu

t shal l continu e to compl

y wit h all othe r Schedule B an

d Pretreatmen

t monitoring requirement s i

n th e permit . Th e non-regulator

y benchmar

k t o us e i n assessin g whethe

r th e applicabl e treatmen

t technolog y i s providing th e highes t an d bes t practicabl e treatmen

t fo r arseni c i n th e discharg e i s onl

y applicabl e unti l th e EP

A take s actio n o n th e propose d inorganic arseni c criterion . pH Th e Willamett

e Basin Wate

r Qualit y Standar d fo r pH i s foun d i n OA R340-041-0345 . Th

e allowe d rang e i s 6. 5 to 8.5 . Generall

y p H permi

t limit s fo r treatmen t plant s rang e fro

m6. 0 t o 9.0 . Thes e limit s ar e base d o n Federa l secondai y treatmen

t standard s fo

r sewag e treatmen

t facilities , an

d ar e applied t o th e majorit

y of NPDE S permittee s i

n th e state . Withi

n th e permittee' s mixing zone , th e wate r qualit y standar d fo r pH doe s no

t have to b e met . Th e Department' s Reasonable Potentia l Analysi s (RPA

) calculate s th e p H of

th e discharg e combine

d wit h th e receivin g strea

ma t the edge of

th e mixin g zone . Base

d o n the assume

d critica l cas e conditions , th e RP

A (se e Attachmen t

7 ) demonstrate s tha

t mixing wit

h ambien t wate r within th e mixin g zone ensure s tha t th e p H meet s th e standard . Monitorin g fo

r p H i s continuous . Whe

n continuou s monitorin

g i s provided , th e permit

allow s th e discharg e t o b e outside th e allowe

d rang e fo r u p to 1 percen

t ( 7 hours an d 2 6 minutes ) of

an y calenda r month . No single excursio n ma

y last longe r tha n on e hour . Th e Departmen

t consider s th e propose d permit limit s t o be protectiv e o f th e wate r qualit y standard . E. coli Bacteria Th e propose d permi

t limit s ar e base d o n th e E. coli standar

d contained i

n OA R340-041-0009(5) . Th

e proposed limit s ar e amonthl y geometric mea

n o f 126 E. coli pe

r 10 0 mL , wit h n o singl e sample exceeding 40 6 E. coli pe r 10 0 mL . I f asingle sampl

e exceed s 40 6 E. coli pe

r 10 0 mL , the n th e permitte e ma

y tak e five consecutive re samples . I f th e lo g mea n of th e five re-sample s i s les s tha n o r equa l to 126 , aviolatio n i s not

triggered . Th

e re sampling mus t

be take n a t fou r hou r interval s beginning withi

n 2 8 hours afte

r th e origina

l sampl e wa s taken . Th e propose d limits ar

e take n directly fro

mth e Orego

n bacteri arul e whic

h i s foun d i n OA R340-041-0009 . Thi s rul e establishe s numeric in-strea mwate r qualit y standard s (OA

R340-041-0009(1)) , establishe s aprohibition agains t discharging ra

w sewage , establishe s effluen t limitation s an

d th e methodology fo

r establishing aviolation (OA R340-041-0009(5)) . Regarding th e genera l condition 6 foun

d i n Sectio n B of Schedule F i

n thi s permi

t which prohibit s overflow s fro mwastewate

r conveyanc e systems , the Environmenta l Qualit y Commissio

n (EQC ) recognize s tha

t i t i s impossible t o design an

d construct

aconveyanc e syste

mtha t wil l preven

t overflow s unde

r al l stor mconditions . Th

e applican t i s no t seeking permi

t coverag e fo

r overflow s an

d th e permi

t doe s no t authoriz e suc

h discharges . Th

e Stat e o f Oregon ha s determine

d tha t all wastewate

r conveyanc e systems shoul

d b e designe d t o transpor t stor mevent s u

p to aspecifi c siz e t

o the treatmen

t facility . Therefore , i

n exercising it s enforcemen

t discretio n regarding Sanitaiy Sewe r Overflows , the Departmen

t wil l conside

r th e following : (1 ) Whethe

r th e permittee ha s conveyanc e an d treatmen t facilitie s adequat

e to preven

t overflow s excep

t during a stor meven t greate r tha n the one-in-five-year , 24-hou r duration stor

mfro mNovembe

r 1 throug h Ma y 2 1 an d OpCertClassWorkshee t

(Rev . 12/03/2008 )Cit y o f

Corvalli s Evaluatio n Repor t Pag e 1 7 excep t durin g astor

meven t greate r tha n th e one-in-ten-year , 24-hou r duratio n stor mfro mMa y 2 2 throug h Octobe r 31 . I n addition , DE Q wil l als o conside r usin g enforcemen t

discretio n fo r

overflow s tha t

occu r durin g a stormeven t

les s than th e one-in-five-year , 24-hou r duratio n stor

mfro mNovembe r

1 throug h May 2 1 i f

th e permitte e ha d separat e sanitai y an d stormsewer s on Januar y 10,1996 , ha d experience d sanitar y sewe r overflow s du e t o inflo w an d infiltratio n problems , an d ha s submitte d an acceptabl e pla n t o th e Departmen t t o addres s thes e sanitai y sewe r

overflow s b y Januar y 1,2010 ; (2 ) Whethe r

th e permitte e ha s provide d th e highes t an d bes t practicabl e treatmen t

and/o r contro l o f

wastes , activities , an d flows an d ha s properl y operate d th e conveyanc e an d treatmen t facilities ; (3 ) Whethe r

th e permitte e ha s minimize d th e potentia l environmenta l an d publi c healt h impact s fromth e overflow ; an d (4 ) Whethe r

th e permitte e ha s properl y maintaine d th e capacit y o f th e conveyanc e system . DE Q wil l revie w th e permittee' s determinatio n o f th e one-in-five-year , 24-hou r duratio n winte r

stor man d th e one-in-te n year , 24-hou r duratio n summe r

stor ma s describe d i n th e Januar y 20 , 199 4 CH2 M Hil l pape r o n "Rainfal l Analysi s an d SF O Desig n Storms " prepare d specificall y fo r Corvallis , Oregon . I n th e even t tha t a permi t holde r report s a n overflo w even t associate d wit h astor meven t an d DE Q doe s no t

hav e informatio n fro m th e permi t

holde r sufficien t

t o determin e whethe r

o r no t th e stor meven t

exceed s stor mevent s a s specifie d i n OA R340-041-0009(6 ) & (7) , DE Q wil l perfor mth e determinatio n usin g th e informatio n containe d i n Figur e 2 6 o f th e 197 3 NOA A Atla s 2 entitle d "Precipitation-Frequenc y Atla s o f th e Wester n Unite d States , Volum e X - Oregon" . Thi s figure i s entitle d "Isopluvial s o f 5-y r 24-h r precipitatio n i n tenth s o f a n inch" . Th e Atla s ca n b e obtaine d o n lin e a t

http://hdsc.nws.noaa . g o vAidsc/pfds/other/orpfds . html , howeve r th e file i s vei y large . A scanne d versio n o f

Figur e 2 6 i s availabl e at : http://www.wrcc.dri.edu/pcpnfreq/or5y24.gif . DE Q wil l compar e th e informatio n i n thi s figur e wit h rainfal l dat aavailabl e fro mth e Nationa l Weathe r Service , o r

othe r sourc e a s necessaiy . I n addition , th e Cit y o f

Corvalli s i n suppor t

o f a n effor t t o develo p SS O complianc e requirement s ha s performe d aflow frequenc y analysi s t o establis h relationship s betwee n rainfal l an d we t weathe r flow i n th e City' s separate d sanitai y sewe r system . Thi s informatio n wa s develope d t o hel p th e Cit y o f Corvalli s defin e th e stor m duration , th e beginnin g o f arainfal l event , an d th e anteceden t rainfal l wit h asingl e 5-yea r frequenc y flow rat e a t specifi c location s i n th e sanitai y sewe r collectio n system . Th e City' s statistica l analysi s o f th e flow rate s i n th e collectio n syste midentifie d th e flow rat e associate d wit h a5-yea r stor mrecurrenc e interva l wit h th e inten t tha t SSO s woul d no t

b e allowe d fo r

measure d flows u p t o an d includin g thi s define d rate . Th e Departmen t ha s informe d th e Cit y o f

Corvalli s tha t

DE Q canno t

predic t whethe r aSS O i s beyon d th e permittee s contro l o r i f i t wil l resul t

i n aviolatio n base d solel y o n th e City' s flow frequenc y analysis . However , th e Departmen t ha s agree d t o revie w th e City' s determinatio n fo r an y singl e overflo w even t i n conjunctio n wit h othe r stor mrelate d informatio n i n orde r

t o suppor t

th e Department s decisio n a s t o whethe r aviolatio n ha s occurred . Chlorine Chlorin e i s adde d t o th e discharg e t o disinfec t th e plan t

effluen t an d compl y wit h th e wast e discharg e limitation s fo r bacteria . Th e minimu mdesig n criteri a(OA R340-041-0007 ) fo r sewag e waste s require s th e Cit y t o provid e disinfectio n facilitie s capabl e o f achievin g 1. 0 mg/ L tota l chlorin e residual . Thi s concentratio n coul d b e considere d atechnolog y base d minimu mconcentration . Chlorin e i s aknow n toxi c substanc e an d a s suc h i s subjec t t o limitatio n unde r

Orego n Administrativ e Rules . Th e rul e (OA R340-041 ) state s i n par t tha t toxi c substance s shal l no t b e discharge d t o water s o f th e stat e a t level s tha t

adversel y affec t

publi c health , aquati c lif e o r othe r designate d beneficia l uses . I n addition , level s o f toxi c substance s shal l no t excee d th e criteri aliste d i n Tabl e 20 , whic h wer e base d o n criteri aestablishe d b y th e EP A an d publishe d i n Qualit y Criteri afo r Wate r (1986) , unles s otherwis e noted . OpCertClassWorkshee

t (Rev. 12/03/2008

)Cit

y o f Corvalli s Evaluatio n Repor t Pag e 1 8 However , OA

R340-04 1 -005 3 state s tha

t th e Departmen

t ma y allo w adesignated portio n of areceivin g wate

r to serv e a s azon

e of dilutio n fo r wastewater s an

d receivin g water s to mi

x thoroughl

y an d thi s zon e wil l be define

d a s amixing zone . Th

e Departmen

t ma y suspen d all o r par t of th e wate r qualit y standards , or

se t les s restrictiv e standards , i

n th e define

d mixin g zone , provided th e wate

r within th e mixin

g zon e i s free of material s i

n concentration s tha

t wil l caus e acut

e toxicit y to aquati c lif

e a s measured b

y th e acut e Whole Effluen

t Toxicit y method an d outside th e boundar

y of th e mixing zon

e i s fre e of material s i

n concentration s tha

t wil l caus e chroni c toxicity . Furthermore , 4 0 CF

R§ 122.44(d

) state s tha t permit limitation s mus t

contro l al l pollutant s o

r pollutan t parameter s which ar e o r ma y b e discharged a

t alevel which wil l cause , hav e th e reasonabl e potentia l to cause , o

r contribut e to a n excursion above an

y stat e wate r qualit y standard , includin g stat

e narrativ e criteri afo

r wate r quality . Th

e fres h wate r criteri afo r chlorine wer

e use d to calculat

e permit limitations . According to OA R340-041 , Tabl e 20 , chlorin e concentration s of

1 1 ug/ L ca n resul t i n chroni c toxicit

y i n fres h water s whil e 1 9 ug/

L ca n resul t i n acut e chlorine toxicit

y i n fres h waters . Complianc e wit

h acut e toxicit y criteri ai s require d a

t th e edg e of

th e Zon e o f Initia l Dilutio n (ZED

) an d complianc e wit

h chroni c toxicit

y criteri ai s require d a

t th e edg e of

th e mixin g zone . Fo r

th e facility , outfall , an

d mixing zone a s presently configured , th e dilutio n facto r i s 3 3 a t th e edg e o f

th e ZI D an d 90 a t th e edg e o f

th e mixing zone durin g critica

l low (summer

) strea mflo w conditions . Permi

t limit s based o

n thes e dilutions , a coefficien t o f varianc e of

0.22 8 an d th e acut e an d chroni c criteri awer

e calculated (see Attachmen t 8) . Th e calculate d permit

limit s are : Shal l no t exceed amonthl

y averag e concentratio n of

0.4 1 mg/ L an d adail y maximu mconcentratio n of 0.6 3 mg/ L Th e curren t permit limit s tota l residua l chlorine to adail

y averag e concentration of

0. 5 mg/1 . Th

e proposed wate r qualit y base d permi

t limit s mus t

be a s restrictiv e a s th e existin g permi t limits . Therefore , th e proposed chlorin e permit

limit s are : Shal l no t exceed amonthl

y averag e concentratio n o f

0.4 1 mg/ L an d adail y maximu mconcentratio n of 0.5 0 mg/ L Excess Thermal

Load A s discussed above , water s i n th e Willamett

e Basin ar e wate r qualit y limited fo

r temperatur

e fro mApri l 1 through Octobe

r 31 . Thi s facilit

y received atemperatur

e Wast e Loa d Allocation s (WLA

) fo r tha t perio d i n th e 200 6 Willamett

e Tota l Maximu mDail y Loa d (TMDL) . Ther

e ar e WL A fo r th e rearin g an

d migration season (Ma y 1 6 through Octobe

r 14 ) an d spawnin g season (April 1 throug

h Ma y 1 5 an d Octobe r 1 5 through Octobe

r 31) . Th e WL A ar e directly convertible t

o Exces s Therma

l Loa d (ETL) limits . Ther

e ar e thre e option s fo

r determining th e ET

L limi t base d o n th e amoun

t o f receivin g strea

mmonitoring th e permitte e i s willin g to perfor man d report . Th

e option s an

d limits ar e a s follows : Optio n A - n o strea mmonitorin

g neede d Durin g the rearin g an

d migration seaso

n (Ma y 1 6 through Octobe

r 14) , the WL

A state s th e permitte e ma

y not discharg e mor

e tha n 10 8 million Kcals/da

y a s arollin g seven-da

y average . However , th e Departmen t i s allowing existin g source s to temporaril y us e th e reserv e capacit

y i n th e TMDL . Thi s i s done b y applying a multiplie r to th e WLA . Durin

g th e rearing period , th e multiplie r allowe d to Corvalli s i s 1.187 . Therefore , the proposed permi

t limit wil l be 128 million Kcals/da y a s arollin g seven-da

y average . During th e spawning seaso

n (April 1 throug

h Ma y 1 5 an d Octobe r 1 5 throug h Octobe r 31) , th e permitte e ma

y no t discharg e mor

e tha n 12 9 millio n Kcals/da y a s arollin g seven-da

y average . Th

e Departmen

t ha s not proposed atemporar

y reserv e capacit

y multiplie r fo r th e cit y o f Corvalli s during the spawning period . OpCertClassWorkshee t

(Rev . 12/03/2008 )Cit y o f

Corvalli s Evaluatio n Repor t Pag e 1 9 Optio n B - streammonitorin g for flo w Th e ET L Limi t

for rearin g an d migratio n perio d may b e calculate d o n adail y basi s whe n rive r flow s ar e reported . Th e ET L ma y b e calculate d usin g th e formula : ETL = (((0.0000781 6 x Q R ) + 0.6532 ) - 0.1389 ) x 11.2 9 x 2.44 7 x (22. 9 - 18 ) x 1.18 7 Th e ET L Limi t

ma y als o b e calculate d o n adail y basi s fo r th e spawnin g perio d whe n rive r flow s ar e reported . Th e ET L ma y b e calculate d usin g th e formula : ETL = (((0.0000978 6 x Q R ) + 0.4072 ) - 0.3077 ) x 11.2 9 x 2.44 7 x (22. 9 - 13 ) Where : Q R - th e rollin g 7-da y averag e ambien t

rive r flo w (cfs ) recorde d a t

USG S Gag e 1416600 0 plu s USG S Gag e 1417000 0 plu s USG S Gag e 1417100 0 adde d together , o r alternatively , us e Corvalli s USG S Gag e 14171600 . Optio n C - strea mmonitorin g fo r flo w an d temperatur e Th e ET L Limi t

fo r rearin g an d migratio n perio d ma y b e calculate d o n adail y basi s whe n bot h rive r flows an d rive r temperature s (both dail y averag e an d dail y maximum ) ar e reported . Th e ET L may b e calculate d usin g th e formula : ETL - (((0.0000781 6 x Q R ) + 0.6532 ) - a) x 11.2 9 x 2.44 7 x (22. 9 - 18 ) x 1.18 7 Th e ET L Limi t

fo r th e spawnin g perio d ma y b e calculate d o n adail y basi s whe n bot h rive r flows an d rive r temperature s ar e reported . Th e ET L ma y b e calculate d a s follows : ETL - (((0.0000978 6 x Q R ) + 0.4072 ) -a)x 11.2 9 x 2.44 7 x (22. 9 - 13 ) Where : Q R = th e rollin g 7-da y averag e ambien t

rive r flow (cfs ) recorde d a

t USG S Gag e 1416600 0 plu s USG S Gag e 1417000 0 plu s USG S Gag e 1417100 0 adde d together , o r alternatively , us e Corvalli s USG S Gag e 14171600 . Th e valu e fo r

a i s determine d base d o n th e relationshi p betwee n th e rollin g seven-day averag e maximu mnatura l therma l potentia l rive r temperatur e i n ° C (TR M N ) , th e rollin g seven-day averag e natura l therma l potentia l rive r temperatur e i n ° C (TRAN ) an d th e applicabl e criteri ai n ° C a s follows : Dail y Ma x NT P Rive r

Temp = (1.080 4 x th e dail y maximu mambien t rive r temperatur e i n °C ) - 2.2 5 Dail y Avg . NT P Rive r

Temp = (1.054 3 x th e dail y averag e ambien t rive r temperatur e i n °C ) - 2.0 7 TRM„N = th e rollin g seven-da y averag e dail y maximu mnatura l therma l potentia l rive r temperatur e (°C) ; an d TRA N = th e rollin g seven-da y averag e dail y averag e natura l therma l potentia l rive r temperatur e (°C ) Durin g rearin g an d migration : I f TR M N i s les s tha n o r

equa l t o 1 8 °C , the n a - 0 I f TRM N i s greate r

tha n 1 8 ° C an d TR

A N i s greate r

tha n o r equa l t o 1 8 °C , the n a ~ 0 I f T RM

_ N i s greate r

tha n 1 8 ° C an d TRA_ Ni s les s tha n 1 8 °C , the n a - 1 - (TRA N - M 8 °C ) Durin g spawning : I f TR M N i s les s than o r

equal t o 1 3 °C , the n a = 0 I f TR M H i s greater

than 1 3 ° C an d TR

A N i s greater

tha n o r equa l t o 1 3 °C , the n a = 0 I f TR M N i s greater

than 1 3 ° C an d TR

A N i s les s tha n 1 3 °C , the n a ~ 1 - (TR A N + 1 3 °C ) OpCertClassWorksheet

(Rev . 12/03/2008 )Cit

y o f Corvalli s Evaluatio n Report Pag e 2 0 Th e limit s ar

e base d o n arollin g seven-da

y average . Therefore , limit s ar e to b e calculated an

d complianc e wil l b e evaluated startin g o

n th e sevent

h da y o f eac h season (Apri l 7 t

h an d Octobe r 21 s 1 fo r spawnin g an d Ma y 22 n d fo r rearing) . Wheneve

r eithe r Option B o

r C i s used , ther

e mus t b e a t leas t seve n day s (six precedin g day s an d th e da y of use ) o f river dat aavailable . I

n addition , wheneve

r eithe r Option B o

r C i s used , th e Discharg e Monitoring Repor

t mus t stat e which option was used an d includ e th e resul t

o f th e ET L limit calculation an

d includ e al l datanecessaiy to calculat e the ET L limit . Shared Watershed

Allocation of

Thermal Load Th e permitte e ma

y participat

e i n aDepartmen

t approved Exces s Therma

l Loa d Sharin g Agreemen

t (Sharing Agreement

) wit h othe r NPDES permittee s (Sharing Partners ) tha t wer e assigned therma

l wast e loa d allocation s fro mth e 200 6 Willamett

e TMDL . Al l therma

l loa d sharin g mus t

b e manage

d i n accordanc e wit

h th e requirement s of

th e Sharin g Agreement . Th

e Agreemen

t an d amendments t

o th e agreemen

t mus t b e submitte

d to th e Departmen

t a t leas t 3 0 day s prior

to implementation an

d approve d b y th e Departmen

t i n writing . Approval s an d amendments to th e Sharin g Agreemen

t ar e not considere d permi

t modifications . Th e permitte e ma y discharg e th e permitted Exces s Therma l Loa d usin g th e option s liste d i

n th e permit , a s allocated b

y the TMDL , plu s temporary reserv e capacit y allocation , plu s an

y borrowed unuse

d portion s of

permitted ET

L fro mSharin g Partner s i n accordanc e wit

h th e Departmen

t approve d Sharin g Agreement . Th

e permitte e ma

y als o shar e an y unused portio n of

it s permitted ET

L including temporar

y reserved capacit

y allocatio n wit

h Sharin g Partner s i

n accordanc e wit

h th e Departmen

t approved Sharin

g Agreement . Th

e permitte e mus t

recor d th e date , time , an

d th e amoun t o f ET L tha t was borrowed fro

mth e anothe

r permitte e unde

r th e Sharin g Agreemen

t o n th e monthl

y Discharg e Monitorin g Repor t (DMR ) an d notif y th e othe r permittee s an

d th e Department' s appropriat e office within 2 4 hour s of th e dat e an d tim e o f th e amoun

t of borrowed ET

L tha t wa s used unde

r th e Sharin g Agreement . I f

th e permitte e exceed s it s permitted ET L limit , i t wil l not b e deeme d i n violatio n of

th e limit i f th e amoun t o f unused ET

L fro mth e Sharin

g Partner s participatin g i n th e Sharin g Agreemen

t o n th e dat e o f th e exceedenc e i s equa

l to o r greate r tha n th e amoun

t of th e exceedenc e an

d a s long a s n o Sharin

g Partner s participatin g i

n the Sharin

g Agreemen

t ha s utilize d th e amoun

t of unuse d ET L o n th e sam e date . Mixing Zone Th e regulator y mixin g zon e i s tha t portio n of the Willamett

e Rive r containe d within aban

d extendin g ou t fro mthe wes t ban k thirt y (30) fee t beyon d the easter

n edge o f th e diffuse r an d extendin g ten (10) fee

t upstrea man d thre e hundre d (300 ) fee t downstrea mfro mth e diffuser. Th

e Zon e o f Immediat e Dilution (ZID ) i s define

d a s tha t portio n of th e regulator

y mixin g zon e tha t i s withi n thirt y (30) fee t of th e poin t of discharge . Th

e Departmen

t propose s to retai n the existing mixin

g zone . Outfall s 003 . 005 . an

d 007 . Combine

d Sewe r Overflow s Th e followin g requirements ar

e i n fulfillmen

t o f th e Nine Minimu

mControl s fo

r the operatio

n an d maintenance o

f the combin

e sewe r systems , a s se t fort h i n EPA' s Combine

d Sewe r Overflo w Policy , a s applicable to th e permittee : (1 ) Th e permittee shall implemen

t prope r operatio n an d maintenanc e programs fo

r th e sewe r syste m an d al l CS O outfall s to reduc e the magnitude , frequency , an d duratio n of CSOs . Th e progra mshal l conside r regula r sewe r inspections ; sewer, catc

h basin , an d regula r cleaning : equipmen

t an d sewe r collection syste

mrepai r o r replacement, wher

e necessaiy ; an

d disconnectio

n o f illega l connections . (2 ) Th e permittee shal

l implemen

t procedure s tha

t will maximiz

e us e of the collection syste

mfo r wastewate r storag e tha

t ca n be accommodate

d b y the storage capacit

y o f the collection syste

mi n orde r t o reduc e th e magnitude , frequency , an d duratio n o f CSOs . (3 ) Th e permitte e shal l revie w an d modify , a s appropriate , its existing pretreatmen t progra mto minimiz e CS O impacts fro

mth e discharge s fro

mnondomestic users . OpCertClassWorkshee t

(Rev . 12/03/2008 )Cit y o f

Corvalli s Evaluatio n Repor t Pag e 2 1 (4 ) Th e permitte e shal l operat e th e POT W treatmen t plan t a t maximu mtreatabl e flo w durin g al l we t weathe r flo w condition s t o reduc e th e magnitude , frequency , an d duratio n o f CSOs . Th e permitte e shal l delive r

al l flows t o th e treatmen t

plan t withi n th e constraint s o f

th e treatmen t

capacity o f

th e POTW . (5 ) Dr

y weathe r overflow s fro mCS O outfall s are prohibited . Eac h dt y weathe r overflo w mus t

b e reporte d t o th e DE Q a s soo n a s th e permitte e become s awar e o f th e overflow . Whe n th e permitte e detect s adr

y weathe r overflow , th e permitte e shal l begi n correctiv e actio n immediately . Th e permitte e shal l inspec t

th e dt y weathe r

overflo w eac h subsequen t day unti l th e overflo w ha s bee n eliminated . (6 ) Th e permitte e shal l implemen t measure s t o contro l soli d an d floatable material s i n CSOs . (7 ) Th e permitte e shal l implemen t apollutio n preventio n programfocuse d o n reducin g th e impac t o f CSO s o n receivin g waters . (8 ) Th e permitte e shal l implemen t apubli c notificatio n proces s t o infor mcitizen s o f

whe n and wher e CSO s occur . Th e proces s mus t includ e (a ) amechanis mt o aler t person s o f

th e occurrenc e o f CSO s an d (b ) asyste mt o determin e th e natur e an d duratio n o f condition s tha

t are potentiall y harmful for

user s o f receivin g water s du e t o CSOs . (9 ) Th e permitte e shal l monito r CS O outfall s t o characteriz e CS O impact s an d th e efficac y of CS O controls . Thi s shal l includ e collectio n o f dat atha t wil l b e use d t o documen t th e existin g baselin e conditions , evaluat e th e efficac y o f th e technolog y base d controls , an d determin e th e baselin e condition s upo n whic h th e long-ter mcontro l pla n wil l b e based . Thes e dat ashal l include : (a ) Characteristic s o f th e combine d sewer

syste mincludin g th e populatio n serve d b y th e combine d portio n o f

th e syste mand location s o f al l CS O outfall s i n th e CSS . (b ) Tota l numbe r

o f CS O event s and th e frequenc y an d duratio n o f CSO s fo r arepresentativ e numbe r o f events . (c ) Location s an d designate d use s o f receivin g wate r

bodies . (d ) Wate r

qualit y dat afor

receivin g wate r

bodies . (e ) Wate r

qualit y impact s directl y relate d t o CSO s (e.g. , publi c acces s closing , floatables wash-u p episodes , fish kills) . Outfal l 012 , Combine d Sewag e Treatmen t Syste mDischarg e Th e Permitte e shal l operat e th e combine d sewe r relie f intercepto r

an d CS O we t

weathe r treatmen t facilitie s t o minimiz e th e frequenc y o f CSO s throug h Outfall s 003,005 , and 007 , an d maximiz e th e volum e o f wastewate r treate d a t th e POT W and th e we t

weathe r treatmen t facility . Capture d combine d sewag e shal l receiv e aminimu mo f secondai y treatmen t

t o th e maximu mextent

practicable . Fo r thos e stor mevent s tha t

excee d th e capacity o f

th e POT W and promp t

th e diversio n o f

combine d sewag e t o th e we t weathe r treatmen t facility , th e combine d sewag e shal l receiv e equivalen t o f primar y treatmen t

an d disinfection . Outfal l 01 4 - Recycle d Wate r Prio r t o irrigatio n of

th e recycle d water , th e discharg e mus t compl y wit

h total coliformlimit s base d o n protectio n o f huma n healt h du e t o huma

n pathogens . Dependin g o n th e selecte d alternativ e o f lan d applicatio n an d th e typ e o f us e for th e recycle d water , th e permitte e may generat e Clas s D , Clas s C , Clas s B o r Clas s A recycle d water . Fo r Clas s B recycle d water , th e recycle d wate r mus t b e oxidize d an d disinfecte d s o a s no t t o excee d amedia

n o f 2. 2 tota l colifor

mbacteri aorganism s pe r

100 mL , base d o

n result s o f

th e las t seve n day s that

analyse s hav e bee n OpCertClassWorkshee t

(Rev . 12/03/2008 )Cit y o f

Corvalli s Evaluatio n Repor t Pag e 2 2 completed , an d 2 3 tota l colifor morganism s pe r

10 0 m L i n an y singl e sample . Fo r Clas s A recycled water , befor e disinfection , th e wastewate r mus t b e treate d wit

h afiltration proces s an d th e turbidity mus t no t excee d an averag e o f 2 nephelometri c turbidity unit s (NTU ) withi n a24-hou r period , 5 NT U mor e than five percen t o f th e tim e withi n a24-hou r period , an d 1 0 NT U a t

an y time . After

disinfection , th e wastewate r mus t no t excee d amedia n o f

2. 2 tota l colifor mbacteri aorganism s pe r

10 0 mL , base d o n results o f

th e las t seve n day s that

analyse s hav e bee n completed , an d 2 3 tota l colifor

mbacteri aorganism s pe r

100 mL i n an y singl e sample . A Recycle d Wate r

Us e Pla n mus t

b e approve d b y th e Departmen t prio r t o th e permitte e lan d applyin g th e treate d recycle d wastewate r

throug h Outfal l 014 . Followin g Departmen t approval , th e land applicatio n o f wastewate r

shal l confor mt o th e Departmen t

approve d plan . Specifi c crops , applicatio n rate s and buffer s wil l b e approve d b y th e Departmen t withi n th e Recycle d Wate r Us e Plan . Th e bacterial effluen t limitation s are achievabl e throug h prope r operatio n and maintenance . Schedul e B - Minimu mMonitorin g an d Reportin g Requirement s Schedul e B describe s th e minimu mmonitorin g an d reportin g necessai y t o demonstrat e complianc e wit h th e condition s o f

thi s permit . Th e authorit y t o requir e periodi c reportin g b y permittee s i s include d i n OR S 468.065(5) . Self-monitorin g requirement s ar e th e primar y means o f ensurin g tha t

permi t limitation s ar e bein g met . However , othe r

parameter s nee d t o b e monitore d t o collec t informatio n whe n insufficien t informatio n exist s t o establis h alimit , bu t wher e ther e i s apotentia l fo r awate r quality concern . Th e Departmen t

ha s develope d amonitorin g matri x for commonl y monitore d parameters . Propose d monitorin g frequencie s fo r

al l parameter s ar e base d o n thi s matri x and , i n som e cases , may hav e change d fro mth e curren t permit . Th e propose d monitorin g frequencie s for al l parameter s correspon d t o thos e o f facilitie s o f

similar siz e an d complexit y i n th e state . Th e permitte e i s required t o hav e alaborator y Qualit y Assurance/Qualit y Contro l program . Th e Departmen t recognize s tha t

som e test s d o no t

accuratel y reflect

th e performanc e o f

atreatmen t

facility du e t o qualit y assurance/qualit y contro l problems . Thes e test s shoul d no t b e considere d whe n evaluatin g th e complianc e o f th e facility wit h th e permi t

limitations . Thus , th e Departmen t i s als o proposin g t o includ e i n th e openin g paragrap h o f Schedul e B astatemen t

recognizin g tha t

som e tes t result s ma y b e inaccurate , invalid , d o no t adequatel y represen t th e facility' s performanc e an d shoul d no t b e use d i n calculation s require d b y th e permit . Belo w i s adiscussio n o f

some o f th e minimu mmonitorin g requirement s containe d i n th e propose d permit : Influen t an d Outfal l 0 0 L 002 , an d 01 2 (Treate d Effluent ) Dail y monitorin g o f

effluen t flow an d calibratio n o f

th e flow mete r

evei y si x month s i s retaine d i n thi s permit . Monitorin g o f

th e influen t

flow i s no t

required. However , th e Cit y may us e th e influen t flow mete r

(whe n properl y calibrated ) i n plac e o f th e effluen t

flow mete r

whe n th e effluent

flow mete r

canno t b e use d (suc h a s whe n th e chlorin e contac t chambe r i s take n ou t

o f servic e fo r

maintenance) . Continuou s monitorin g o f th e influen t

and effluent

fo r p H ha s bee n retained . Monitorin g o f th e influen t

an d effluen t fo r CBOD 5 an d TS S i s retaine d a t thre e time s pe r

week . Pound s o f

CBOD 5 an d TS S i n th e discharg e mus t b e calculate d a t

th e sam e frequency . Th e Cit y ha s previousl y requeste d that effluent limit s (concentration , mas s and percen t

removal ) b e base d o n CBOD 5 rathe r tha n BOD 5 . Federa l secondai y treatmen t standard s requir e municipa l source s t o achiev e aspecifi c CBOD 5 an d TS S removal efficienc y a s amonthl y average . Reportin g o f th e remova l efficiencie s i s require d i n th e curren t permi t an d no change s ar e proposed . Th e propose d permi t

require s monitorin g o f

th e effluen t

fo r tota l chlorin e residual o n adail y basi s t o confir m consisten t performanc e o f

th e disinfectio n system . Th e amoun t o f chlorin e use d eac h day mus t als o b e OpCertClassWorkshee

t (Rev . 12/03/2008 )Cit

y o f Corvalli s Evaluatio n Report Pag e 2 3 monitored . Bacteri amonitoring o f th e effluen

t fo r E . coli ha s bee

n retaine d a

t thre e time s pe

r week . Monitoring fo r E . coli mus t

b e performe

d i n accordanc e wit

h on e of th e method s approve

d b y EPA . Ammoni amonitorin g i s require d becaus e CBOD 5 replace s BOD 5 . Monitoring mus t b e performe

d o n th e sam e sample s a s CBOD 5 s o th e Departmen t propose s to continu e monitoring a t thre e time s pe

r wee k monitoring . Continuou s temperatur

e monitoring o f

th e effluen

t i s require d yea

r round . Th

e daily maximu

mtemperatur

e mus t b e reporte d o

n th e monthl

y Discharg e Monitorin g Report . Th e permitte e wil l als o b e require d to calculat e th e rollin g 7-da

y averag e of

th e daily maximu

meffluen t temperature s an

d th e rollin g 7-da

y averag e o

f th e therma l loa d discharge d fro

mApri l 1 through Octobe

r 31 . Thes e ar

e ne w requirements . I n orde r to full y characteriz e th e facility' s contributio n of nutrient s to th e receivin g stream , th e Departmen t i s proposin g to requir

e monitoring of

th e treate d effluen

t fo r nutrients . During th e perio d fro mMa y throug h October , weekl

y monitoring of

th e effluen

t fo r nutrient s (Tota

l Kjeldah l Nitrogen (TKN) , nitrat

e plu s nitrit

e an d tota l phosphorus ) shall b e require d during th e first yea r of th e permit . Afte

r on e year , monitoring of

th e effluen

t fo r nutrient s ma

y b e eliminated unles s notified i n writin g b

y th e Department . Th e propose d permit

require s continue d monitoring o f th e influen

t an d effluen t fo r metal s an d cyanid e semi annuall y usin g 3 consecutiv e day s betwee n Monda y an d Friday , inclusive . Result s ar e to be submitted wit

h th e Pretreatmen

t Progra mAnnua l Report . Submitta

l o f metal s monitorin g result s wit h th e monthl

y Discharg e Monitorin g Repor

t i s not required . Th e propose d permit

require s annua

l whole effluen

t toxicit y (WET ) test s fo r fou r year s using thre e species , o r quarterly fo

r on e calenda

r year . I f th e result s o f

th e firs t fou r annua l test s show tha

t th e effluen

t i s not toxic , n o furthe r Whol e Effluen t Toxicit y testin g wil l b e require d during thi s permit . Whole Effluen t Toxicit y test s ar e to be conducted i

n accordanc e wit

h EP A tes t method s an

d procedura

l requirement s a s define

d i n Schedule D . Th e propose d permit

require s th e Cit

y to monitor

th e effluen

t fo r metal s (except

arsenic) , cyanide , tota

l phenoli c compound s an

d hardnes s semi-annuall

y ove r thre e consecutiv e day s fo

r five years . I

n addition , Arseni c i s to b e monitored quarterly fo

r tw o an d on e hal f years . Th e permitte e mus t

perfor m"priorit y pollutant " scan s fo

r organi c pollutant s i

n orde r to complet

e Par t D of EP A For m2 A fo r th e nex t renewa l application . Three scan s ar e require d durin g th e tw o year s afte r permit issuance . Two of

th e thre e scan s mus t

b e performe

d n o fewe r tha n fou r month s an

d n o mor e tha n eigh t month s apart . Tes t method s used mus t

have quantitatio n limit s les s tha n o r equa l to thos e liste d i

n th e table s i

n Schedule B unles s otherwis e approved b y th e Departmen

t i n writing . Biosolid s OA R340 , Divisio n 50 , "Lan

d Application of

Domesti c Wastewate

r Treatmen t Facilit y Biosolids , Biosolid s Derived Products , an

d Domesti c Septage " require s monitoring an d reporting of

specifi c sludg e parameter s unde r Section 35 . Thes e parameter s ar e identified i

n Schedul e B unde

r "Biosolid s Management " an d include : Tota

l solids , Volatil e solids , Nitrogen , eleve n metal s (Ag , As , Cd , Cr , Cu , Hg , Mo , Ni , Pb , S e & Zn) , Phosphorus , Potassiu man d pH . I n orde r to demonstrat

e complianc e wit

h pathoge n reductio n requirements , th e proposed permit require s monitorin g of

biosolid s fo

r feca l coliform . Th

e Permitte e ma

y us e an y alternativ e method of

demonstrating complianc e wit

h pathoge n reductio n requirement s approved unde r 40 CF RPar t 503.3 2 an d a s listed i

n th e Departmen

t approved Biosolid s Managemen t Plan . I n orde r t o demonstrat

e complianc e wit

h vector attractio n reductio n requirements , the proposed permit require s monitorin g of

percen t volatil e solid s reduction . Th e Permitte e ma

y us e an y alternativ e method o f

demonstratin g complianc e wit h vecto r attractio n reductio n requirement s i

n accordanc e wit

h OA R340-05 0 an

d a s liste d i

n th e Departmen

t approved Biosolid s Managemen t Plan . Th e permitte e mus t

als o record lan

d applicatio n information abou t th e biosolid s tha

t ar e beneficiall

y used . OpCertClassWorkshee t

(Rev . 12/03/2008 )Cit

y o f Corvalli s Evaluatio n Report Pag e 2 4 Reporting Th e reporting perio d i s the calenda r month . Discharg e monitorin g report s mus t b e submitted to th e Departmen t monthl y b y th e 15t h da y of th e followin

g month . Th

e monitoring report s need to identif y th e principa

l operator s designated b

y the Permitte e t o supervis e the treatmen t an d collectio n systems . Th

e reports mus t

als o includ

e record s concerning applicatio n o f biosolid s an

d all applicabl e equipmen

t breakdown s an

d bypassing . Schedule B of

the permit include s th e requiremen

t fo r th e submitta

l o f fou r annua l reports . Th e permitte e must submi t a n annua l repor t o n inflo w an

d infiltration reductio n activities , arepor t o n recycled wate

r utilization , a repor t o n biosolid s handlin g an

d sludg e disposa

l activitie s an

d arepor t o n activitie s undertake

n to implemen

t th e Nin e Minimu

mControl s relate d to EPA' s Combine d Sewe r Overflow Policy . Schedul e D - Specia l Condition s Th e permi t contain s eleve

n specia l conditions . Th

e requirements include : 1 . Th e first conditio n describe s th e seasona l delineatio n o f

th e secondaiy treatmen

t works an d the CS O facility . 2 . Biosolid s b e manage

d i n accordanc e wit

h th e approved biosolid s managemen t plan . 3 . Th e permi t ma y b e modified to incorporat e change s i

n federa l biosolid s standards . 4 . Th e permitte e mus t

notif y th e Departmen

t of malfunctions . 5 . Th e permitte e mus t

hav e th e facilitie s supervise d b y personnel certified b

y th e Departmen

t i n th e operation o f

treatmen t and/or collection systems . 6 . Th e permitte e i s require d to compl y wit h th e rule s concernin g th e us e of recycled wate

r an d th e Recycled Wate

r Us e Pla n approve d b y th e Department . 7 . Th e permitte e shall conduc t

Whole Effluen

t Toxicit y Testing . 8 . An y recycled wate

r used a t th e treatmen

t plan t sit e fo r landscap e irrigation will be exemp t fro mOA R 340-05 5 provided th e reclaime d wate r receive s secondar

y treatmen t an d disinfection . 9 . Th e permitte e ma

y develop awate

r qualit y tradin g progra

mto hel p mee t th e therma

l limits . 10 . Th e Permitte e shall b e require d to submi t updated Mixing Zon

e dilution s using acente

r lin e approac

h wit h th e nex t permi t renewa l application . 11 . Th e permitte e mus t

submit a n Arseni c Quantification Plan . Schedul e E - Pretreatmen

tProgra m Th e curren t permi t contain s twelv e condition s tha t ar e standar d fo r mos t citie s i n Orego n tha t have Industria

l Pretreatmen

t Programs . Thes e twelv e condition s wer e las t update d i n Decembe

r 2008 . Thi s Schedule implements th e requirement s o f apretreatmen

t progra ma s require d b

y Par t 403. 8 of th e Cod e o f Federa l Regulations . Th

e Departmen

t i s proposin g t

o includ e thes e updated condition s i n th e proposed permit . Schedule F - NPDES Genera l Conditions Al l NPDES permit s issue

d i n th e Stat e of Orego n contai n certain condition s tha

t remai n the sam e regardles s o f the typ e of discharg e an

d th e activit

y causing th e discharge . Thes e condition s ar e calle d Genera l Conditions . OpCertClassWorkshee t

(Rev . 12/03/2008 )Cit

y o f Corvalli s Evaluatio n Report Pag e 2 5 Thes e condition s ca

n b e changed o

r modifie d onl y o n astatewid

e basis . Th

e Septembe

r 18 , 2009 edition i s included a s Schedule F of

th e draf t permit . Section A contain s standar

d condition s which includ

e complianc e wit

h th e permit , assessmen

t of penalties , mitigatio n o f

noncompliance , permit

renewa l application , enforcemen

t actions , toxi c discharges , propert y right s an d reference d rule s an

d statutes . Section B contain s requirement s fo r operatio n an

d maintenanc e of

th e pollutio n contro l facilities . Thi s section include s condition s fo r prope r operatio n an

d maintenance , dut

y to hal t or reduc e activit

y i n orde r to maintai n compliance , bypas s o f treatmen t facilities , upse

t conditions , treatmen

t o f singl e operationa

l events , overflow s fro

mwastewate

r conveyanc e system s an

d associated pum

p stations , publi c notificatio n of

effluen t violatio n o

r overflow , an

d disposa l of remove d substances . Sectio

n C contain s requirement s fo

r monitoring an

d reporting . Thi s section include s condition s fo r representativ e sampling , flo w measurement , monitoring procedures , penaltie s o f tampering , reportin g of

monitoring results , additiona l monitorin g b y the permittee , averagin g of measurements , retentio n of records , content s o f

records , an

d inspectio n an

d entry . Sectio

n D contain s reporting requirement s an d include s condition s fo

r reporting planned changes , anticipate d noncompliance , permit transfers , progres s o

n complianc e schedules , noncomplianc e which ma y endange r publi c healt

h or th e environment , othe

r non-compliances , an

d othe r information . Sectio

n D als o contain s signator

y requirement s an

d the consequence s of

falsifyin g reports . Section E contain s th e definition s used throughou

t th e permit . Th e Genera l Condition s wer

e revise d i n 2008/2009 . A summar

y of th e change s i s a s follows : • Ther e ar e additiona l citation s t

o th e federa

l Clea n Wate r Act an d CFR , includin g reference s to standard s fo r sewag e sludg e us e or

disposal . • Ther e i s additiona

l languag e regardin g federa l penalties . • Bypas s languag e ha s bee n mad e consisten

t wit h th e Cod e of Federa l Regulations . • Overflow languag e ha s bee n modified . Formerl

y th e languag e stated tha

t overflow s i

n respons e to th e five o r te n yea r even t woul d not violat e th e permit . No w i

t state s tha t overflow s ar

e prohibited . DE

Q wil l continu e to exercis e enforcemen t discretion wit

h respec t to overflow s consisten

t wit h the provision s o f th e Bacteri aRule (OA

R340-041-0009) . • Reporting requirement s regardin g overflow s have bee n mad e mor e explicit . • Requirement s regardin g emergenc y respons e an

d publi c notification plan s hav e bee n mad e mor e explicit . • Languag e pertainin g t o dut y to provide informatio

n ha s bee n mad e mor e explicit . • Confidentialit

y of information i s addressed .

OpCertClassWorkshee t

(Rev . 12/03/2008 )

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i n

### Attachmen t5 Antidegradation Revie

w Shee t ANTIDEGRADATIO

N REVIE W SHEET FORA PROPOSE

D INDIVIDUA

L NPDE S DISCHARG

E 1 . Wha

t i s th e nam e o f Surface Wate

r tha t receive s th e discharge ? Willamett e Rive r Briefl y describ e th e propose d activity : Municipa l wastewate

r treatmen t I s thi s revie

w fo r (rene^y_ l O

Rnew (circle one ) permit application ? G o to Ste p 2 . 2 . I s thi s surface wate

r a n Outstanding Resourc

e Wate r o r upstrea m fro ma n Outstandin

g Resourc e Water ? No . G o to Ste p 3 . 3 . I s thi s surface wate

r aHig h Qualit y Water ? No . G o to Ste p 4 . 4 . I s thi s surface wate

r aWater Qualit

y Limite d Water ? Yes . G o to Ste p 14 . 14 . Wil l th e proposed activit

y result in aLowerin

g o f Wate r Qualit y i n th e Water Qualit

y Limited Water ? [se

e OA R340-041-0004(3)-(5 ) fo

r adescriptio n i n rul e o

f discharge s tha

t d o not resul t i n lowering o f wate r qualit y o r d o not constitut e ane w and/o r increased discharg e o

r ar e otherwis e exemp

t fro mantidegradation review ; otherwis e see "I s a n Activit y Likel y to Lowe r Wate r Quality? " i

n Antidegradation Policy Implementation Internal Management

Directive for NPDES Permits and Section 401 Water

Quality Certifications] No . Procee

d wit h Permi t Application . Applican

t shoul d provid e basi s fo r conclusion . G

o t o Ste p 21 . Thi s conclusion i s explained an d supported b y dataan

d evaluation s include d wit

h th e Permi

t Evaluation Repor t an d attachment s accompanyin g th e propose d NPDES Permi t Renewal . Thi s i s a

n existing discharg e an

d ther e i s n o chang e in their

operation . Th

e discharg e mus t

mee t th e wate r qualit y criteri a fo r al l parameter s a

t th e edge o f th e mixing zone . Ther

e i s no reques t

fo r amas s loa

d increase . Wast e loa d allocation s assigned b

y th e Willamett

e Basi n TMD L t o thi s sourc e hav e bee

n incorporate

d into th e permi

t b y thi s permi

t renewal . 21 . O n th e basi s o

f th e Antidegradatio n Review , th e followin g i s recommended : _X

_Procee

d wit h Applicatio n t

o Interagency Coordination an d Publi c Commen

t Phase . Den y Application ; retur

n to applican

t an d provid e publi c notice . Actio n Approve

d Section :

### Revie

w Prepared By : Mar k E . Hamli n Phone : (503 ) 378-5 3 l. J Dat e Prepared : Marc h 19 , 2007 ^ Pleas e provide th e followin

g information and submi

t wit h th e completed applicatio n for mto : Departmen

t o f Environmenta

l Qualit y Wate r Qualit y Division—Surfac e Wate

r Managemen

t 81 1 S W Sixt h Avenue Portland , Orego

n 97204-139 0 Name : Address : Phone : Cit

y o f Corvalli s P.O . Box 108 3 Corvallis , O

R97339-108 3 54 1 754-175 7

OpCertClassWorkshee t

(Rev . 12/03/2008 )

### Attachmen t 6 Operato r Certificatio n Workshee t Genera l Requirement s (OA R 340-049-0015 ) - Eac h owne ro f a regulate d wastewate rsyste m mus t hav e it s syste m supervise d b y on e o rmor e operator s wh o hol d a vali d certificat e fo rth e typ e o f system , wastewate rtreatmen t o rcollection , a t a grad e equa l t o o rgreate rtha n th e wastewate rsyste m classificatio n a s define d i n OAR-340-049-002 0 an d 0025 . Becaus e classificatio n establishe s th e operato rcertificat e typ e an d grad e require d fo rcompliance , i t mus t b e determine d prio rt o start-u p o f a ne w o rupgrade d facility . Wastewate rtreatmen t syste m classification s ar e derive d fro m th e tota l point s assigne d base d o n criteri a show n i n OA R 340 - 049-002 5 (se e Ste p 1 o f th e worksheet) . Pursuan t t o OA R 340-049-0020(4) , i f th e complexit y o f a treatmen t syste m i s no t reflecte d i n -0025 , DE Q ma y classif y a syste m highe ra s lon g a s th e designatio n i s consisten t wit h th e inten t o f th e classificatio n syste m (se e Ste p 2 o f th e worksheet) . Collectio n syste m classification s ar e base d o n a servic e are a desig n populatio n t o b e handle d b y th e wastewate rtreatmen t facilit y (se e footnot e o n pag e 1 o f worksheet) . Lik e treatment , i f deeme d appropriate , DE Q ma y classif y th e syste m highe r tha n b y populatio n alon e (OA R 340-049-0020(5)) . Fo rexample , th e desig n servic e are a populatio n fo r"X " Sanitary Distric t i s 135 0 (Clas s I) , bu t ther e ar e 28 0 city-maintaine d STE P o rSTE G unit s an d a chemica l fee d syste m fo rcontro l o f hydroge n sulfide . A Clas s I I designatio n ma y b e appropriat e t o mee t th e inten t o f th e classificatio n syste m t o establis h minimu m operato rrequirement s fo rexperienc e an d knowledge . Upo n writte n notic e t o th e wastewate rsyste m owner , DE Q may chang e th e classificatio n o f a wastewate rsyste m an d giv e th e owne rreasonabl e tim e t o compl y wit h requirement s o f th e ne w classificatio n (OA R 340-049-0020(6)) . I f yo u hav e an y questions , pleas e contac t th e Operato rCertificatio n Progra m offic e i n Th e Dalle s a t (541 ) 298-725 5 x35 . Classificatio n o f Wastewate rSystem s (OA R 340-049-0020 ) Al l wastewate rsystem s regulate d unde rOA R 340-04 9 wil l b e classifie d b y DE Q a s wastewate rtreatmen t system s and/o rwastewate rcollectio n systems , a s appropriate , i n accordanc e wit h th e followin g classificatio n system :

Wastewate rTreatmen t System s Clas s I - 3 0 tota l point s o rles s Clas s I I - 31-5 5 tota l point s Clas s II I - 56-7 5 tota l point s Clas s I V - 7 6 o rmor e point s Wastewate rCollectio n System s Clas s I -1,50 0 o rles s desig n populatio n Clas s I I -1,50 1 t o 15,00 0 desig n populatio n Clas s II I -15,00 1 t o 50,00 0 desig n populatio n Clas s I V - 50,00 1 o rmor e desig n populatio n Definition s use d i n thes e regulation s unles s otherwis e require d b y contex t (se e OA R 340-049-0010) : "Averag e Dr

y Weathe rFlow " (ADWF ) mean s th e desig n averag e dry weathe rflo w capacit y o f th e wastewate rtreatmen t syste m i n gallon s pe rda y o rMillio n Gallon s pe rDay (MGD) , a s approve d b y th e Department . "Industria l Waste " mean s liqui d waste s fro m a n industria l o rcommercia l proces s discharge d int o a wastewate rsyste m fo r conveyanc e an d treatment . "NPDE S Permit " mean s a wast e discharg e permi t issue d i n accordanc e wit h requirement s an d procedure s o f th e Nationa l Pollutan t Discharg e Eliminatio n Syste m authorize d b y Sectio n 40 2 o f th e Federa l Clea n Wate rAc t an d OA R 340 , Divisio n 45 . "Population " mean s th e desig n populatio n o f th e wastewate rsyste m represente d a s th e numbe ro f peopl e o rth e populatio n equivalen t th e syste m i s designe d t o serve . Equivalen t populatio n ordinaril y i s determine d base d o n 7 0 gallon s pe rperso n pe rda y averag e dr

y weathe rflo w (ADWF ) o r0.1 7 lbs . BOD 5 pe rperso n pe rday , whicheve ri s greater . "Wastewater " o r"sewage " mean s th e water-carrie d huma n o ranima l wast e fro m residences , buildings , industria l establishment s o rothe rplaces , togethe rwit h suc h groundwate rinfiltratio n an d surfac e wate ra s ma y b e present . Th e admixtur e o f domesti c an d industria l wast e o rothe rby-products , suc h a s sludge , i s als o considere d wastewate ro rsewage . "Wastewate rTreatmen t System " o r"Sewag e Treatmen t System " mean s an y structure , equipmen t o rproces s fo rtreatin g an d disposin g of , o rrecyclin g o rreusin g wastewate ran d sludg e (includin g industria l waste ) tha t i s discharge d t o th e wastewate r system . "Wastewate rCollectio n System " o r"Sewag e Collectio n System " mean s th e trunks , arterials , pumps , pump/lif t stations , pipin g an d othe rappurtenance s necessar y t o collec t an d carr y awa y wastewate ro rothe rliqui d wast e treatabl e i n a communit y o rprivat e wastewate rtreatmen t facility . "Wastewate rSystem " mean s "Sewag e Treatmen t Works " define d i n OR S 448.40 5 a s an y structure , equipmen t o rproces s require d t o collect , carr y awa y an d trea t domesti c wast e an d dispos e o f sewag e a s define d i n OR S 454.010 . Typically , component s o f a wastewate rsyste m includ e a wastewate rcollectio n syste m an d a wastewate rtreatmen t system . "WPC F Permit " mean s a Wate rPollutio n Contro l Facilitie s permi t t o construc t an d operat e a collection , treatmen t and/o r disposa l syste m wit h n o discharg e t o navigabl e waters .Attachmen t 6 Operato r Certificatio n Workshee t W W Syste m Commo n Name ; Cit y o f Corvalli s Wastewate rReclamatio n Plan t (WWRP ) Facilit y ID : 2015 1 Location : 130 4 N E Secon d St. , Corvallis . Orego n Tota l Points (fro m pag e 3) : U J WW T Clas s (check) : • I Ql l D I N 

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### i v Desig n Population 1 :138.00 0 WW C Clas s (check) : • I • I I • II I EEII V Desig n ADW F loa d (Influen t MGD) 9 7 Desig n BO D loa d (Influen t Ibs./day ) Classifie d bv : Rober

t A . Dicks a Date : 08/18/201 0 Date thi s classificatio n file d wit h th e Operato rCertificatio n Office : Syste m start-u p dat e fo rthi s classificatio n (new , upgrad e o rexpansion) : I s thi s a chang e fro m a prio rclassification ? (check) : • Ye s __<_ N o STE P 1 - Criteri a fo rClassifyin g Wastewate rTreatmen t System s (OA R 340-049-0025 ) (1 ) Desig n Populatio n o rPopulatio n Equivalen t Points (1 0 Points Maximum ) • Less tha n 75 0 0. 5 point s D75 1 t o 200 0 1 poin t Q200 1 t o 500 0 1. 5 point s D500 1 t o 10,00 0 2 point s (X ] Greate rtha n 10,00 0 3 points+ 1 pt . forea . add . 10 k Par t 1 Subtota l 1 7 points (2 ) Averag e Dr

y Weathe rFlo

w (Desig n Capacity

) Point s (1 0 points Maximum ) • Less tha n 0.07 5 MG D 0. 5 poin t • Greate rtha n 0.07 5 t o 0. 1 MG D 1 poin t • Greate rtha n 0. 1 t o 0. 5 MG D 1. 5 point s • Greate rtha n 0. 5 t o 1. 0 MG D 2 point s |X ] Greate rtha n 1. 0 MG D 3 points+ 1 pt . fo r ea . add . MG D Par t 2 Subtota l 1 3 point s (3 ) Uni t Proces s Point s (Chec k ai l tha t apply ) Preliminar y Treatmen t an d Plan t Hydraulics : Se e als o STE P 2 • Comminutio n (cutter , shredder , grinder , barminutor , etc. ) 1 poin t 1 See "Population " definition . Us e th e desig n averag e dail y equivalen t loa d pe r perso n fo r Influen t Flo w o r Influen t BOD5 , whicheve r

i s greater . Thi s valu e i s use d to determin e th e Collectio n Syste mClassification .• Gri t Removal , gravit y 1 poin t [X ] Gri t Removal , mechanica l 2 point s [X ] Screen(s) ( in-sit u o rmechanica l (coars e solid s only ) 1 poin t [X ] Pump/Lif t Station(s ) (pumpin g of mai n flow) 2 points • Flo w Equalizatio n (an y type ) 1 poin t Subtota l 5 points Primar y Treatment : • Communit

y Septi c Tank(s ) (STEP , STEG , etc ) 2 point s [X ] Clarifier(s ) 5 points • Flotatio n Clarifier(s ) 7 points • Chemica l Additio n Syste m 2 points • Imhof f Tanks , (larg e septi c tan k o rsimila rsedimentatio n _digestion ) 3 points Subtota l 5 points Pag e 1 Subtota l 40 point s Pag e 1 of 3 Uni t Proces s Points -

Continue d (Chec k

al l that apply) , Secondary , Advanced , an d Tertiar y Treatmen t Se e als o STE P 2 : • Lo w Rat e Tricklin g Filter(s ) (n o recirculation ) 7 points G Hig h Rate Tricklin g Filter(s ) (recirculation ) 1 0 points Hl_ Tricklin g Filte r- Solid s Contac t Syste m 1 2 points • Activate d Sludg e (include s SB R & basi c MB R process ) 1 5 points • Pur e Oxyge n Activate d Sludg e 2 0 points • Activate d Bi o Filte rTowe rles s tha n 0. 1 MG D 6 point s • Activate d Bi o Filte rTowe rgreate rtha n 0. 1 MG D 1 2 points • Rotatin g Biologica l Contactor s 1 t o 4 shafts 7 points • Rotatin g Biologica l Contactors , 5 o rmor e shafts 1 2 points • Stabilizatio n Lagoons , 1 t o 3 ceil s withou t aeratio n 5 points • Stabilizatio n Lagoons , 1 o rmor e cell s wit h primar

y aeratio n 7 point s • Stabilizatio n Lagoons , 2 o rmor e cell s wit h ful l aeratio n 9 points • Recirculatin g Grave l Filte r7 point s • Chemica l Precipitatio n Unit(s ) 3 point s • Gravit y Filtratio n Unit(s ) 2 point s • Pressur

e Filtratio n Unit(s ) 4 point s • Nitroge n Removal , Biologica l (BNR ) o rChemical/Biologica l Syste m 4 point s • Nitroge n Removal , Designe d Extende d Aeratio n Onl y (Nitrification ) 2 point s • Phosphoru s Remova l Unit(s ) 4 point s • Effluen t Microscreen(s ) 2 point s • Chemica l Flocculatio n Unit(s ) 3 point s • Chemica l Additio n Syste m @ 2 points (describe) : point s Subtota l 1 2 points Solid s Handlin g (Exclude s long-ter m storag e i n lagoon s above ) Se e als o STE P 2 : • Anaerobi c Primar

y Sludg e Digester(s ) w/

o Mixin g an d Heatin g 5 point s • Anaerobi c Primar

y Sludg e Digester(s ) wit h Mixin g an d Heatin g 7 point s OpCertClassWorkshee t

(Rev . 12/03/2008 )__ Anaerobi c Primary an d Secondary Sludg e Digester s 1 0 point s

[X ] Sludg e Digeste rGa s reus e 3 point s • Aerobi c Sludg e Digester(s ) 8 point s [X ] Sludg e Storag e Lagoon(s ) (Lis t Basin(s ) o rTank(s ) unde rSTE P 2 ) 2 point s • Sludg e Lagoon(s ) wit h aeratio n 3 point s • Sludg e Dryin g Bed(s ) 1 poin t [X ] Sludg e Ai ro rGravit y Thickenin g 3 point s • Sludg e Composting , I n Vesse l 1 2 point s • Sludg e Belt(s ) o rVacuu m Press/Dewaterin g 5 point s • Sludg e Centrifuge(s ) 5 point s • Sludg e Incineratio n 1 2 point s • Sludg e Chemica l Additio n Unit(s ) (alum , polymer , alkalin e stab , etc. ) 2 point s • Non-Beneficia l Sludg e Disposa l (landfil l o rburial ) 1 poin t __<_ Beneficia l Sludg e Utilizatio n (se e als o STE P 2 ) 3 point s Subtota l 2 1 point s Disinfection : [X ] Liqui d Chlorin e Disinfectio n 2 point s • Ga s Chlorin e Disinfectio n 5 point s [E l Dechlorinatio n Syste m 4 point s • Othe rdisinfectio n system s includin g ultraviole t an d ozonatio n 5 point s Subtota l 6 point s Pag e 2 Subtota l 3 9 point s Pag e 2 o f 3 (4 ) Effluen t Permi t Requiremen t Point s (Chec k a s applicable ) Se e als o STE P 2 : • Minimu m o f secondar y effluen t limitation s fo rBO D and/o rTS S 2 point s • Minimu m o f 2 0 mg/ L BO D and/o rTota l Suspende d Solid s 3 point s [X ] Minimu m o f 1 0 mg/ L BO D and/o rTota l Suspende d Solid s 4 point s • Minimu m o f 5 mg/ L BO D and/o rTota l Suspende d Solid s 5 point s • Effluen t limitation s fo reffluen t oxyge n (Fo rothe rlimit s se e Ste p 2 ) 1 poin t Par t 4 Subtota l 4 point s (5 ) Variatio n i n Ra w Wast e Points . Point s i n thi s categor y wil l b e awarde d onl y whe n condition s ar e extrem e t o th e exten t tha t operatio n an d handlin g procedur e change s ar e neede d t o adequatel y trea t wast e du e t o variatio n o f ra w wast e (strengt h o rflow ) H__ Recurrin g deviation s o rexcessiv e variation s 100 % t o 200 % 2 point s • Recurrin g deviation s o rexcessiv e variation s o f mor e tha n 200% , o r conveyanc e an d treatmen t o f industria l waste s b y pretreatmen t progra m 4 point s • Septag e o rtruck-haule d wast e 2 point s Part 5 Subtota l 2 point s OpCertClassWorkshee t

(Rev . 12/03/2008 )(6 ) Samplin g an d Laborator y Testin g Points (chec k

a s applicable ) • Sampl e fo rBOD , Tota l Suspende d Solid s performe d b y outsid e la b o r2 point s [X ] BO D o rTota l Suspende d Solid s analysi s performe d a t treatmen t plan t 4 point s • Bacteriologica l analysi s performe d b y outsid e la b o r1 poin t __<_ Bacteriologica l analysi s performe d a t WWT plan t la b 2 point s • Nutrient , Heav

y Metal s o rOrganic

s analysi s performe d b

y outsid e la b o r3 point s (<1/mo . 1 pt) |X l Nutrient , Heav

y Metal s o rOrganic

s analysi s performe d a

t WW T plan t 5 point s Par t 6 Subtota l H point s Part s 4- 6 Tota l 1 7 points * OA R 340-049-002 5 Accumulate d Points . pg 1 40 , pg 2 3 9 & pg3 * 17_ = 9 6 G o t o Ste p 2 T STE P 2 - Complexit y No t Reflecte d Abov e (OA R 340-04 9 0020(4) ) Note : Thi s ste p ma

y justif y a highe rclassification . Points show n ar e give n a s guidance . • Fin e Scree n Preliminar y Treatmen t (include s washin g & compaction ) 2 point s [X ] SCAD A o rsimila rinstrumentatio n providin g dat a w / proces s op . (2- 4 pts ) point s • Pos t aeration , include s mechanica l an d diffuse d aeratio n (no t cascade ) 1 poin t • Clas s A recycle d wate r(storage , distributio n & monitoring ) 6 point s • Clas s B , C , D an d non-disinfecte d recycl e (surfac e & subsurface ) 3 point s • Sludg e dewaterin g usin g ba g o rtub e syste m 1 poin t D Composting , AS P o rwindrow 6 point s n Lan d applicatio n o

f biosolid s b

y syste m operato r(ad d t o BS U pts . Pg . 2 ) 5 point s I I Odo ro rcorrosio n contro l (separat e o rcombined ) 2 point s • Chemical/Physica l advance d wast e treatmen t (10-1 5 points ) point s • Revers e Osmosi s o rElectro-dialysi s 1 5 point s |X ] Othe rEffluen t Requirements @ 1 p t (describe) : Ci2 , NH3 , temp . 3 point(s ) [X j Othe r(describe) : Wet weathe rtreatemen t 1 0 point(s ) OA R 340-049-0020(4 ) point s 1 5 point s Accumulate d Poin t Tota l - Step s 1 an d 2 (ente rher e an d o n pag e 1 ) H I point s A COP Y O F THI S COMPLETE D WORKSHEE T T O B E FILE D WIT H TH E OPERATO R CERTIFICATIO N PROGRA M OFFICE , W Q DIVISION , PRIO R T

O SYSTE M START-U P

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