Stat e o f Orego n Departmen t o f Environmenta l Qualit y 

### NATIONA L POLLUTAN T DISCHARG E ELIMINATIO N SYSTE M WAST E DISCHARG E PERMI T EVALUATIO N AN D FAC T SHEE T

Apri l 201 5 

## Orego n Departmen t

o f Environmenta l Qualit y Wester n Regio n 402 6 Pah-vie w Industria l Dr . Sale mO R9730 2

Permittee : Existin g Permi t Information :

Sourc e Contact : Sourc e Location : LLI D Receivin g Strea m Propose d Action :

Sourc e Categor y Permi tWriter : Cascad e Pacifi c Pulp , LL C 3048 0 America n Dr , P O Bo x 40 0 Halsey , O R9734 8 Fil e Number : 3633 5 Permi t Number : 10111 4 Expiratio n Date : Novembe r 30,201 5 EP A Referenc e Number : OR000107- 4 Lis aScot t (541)369-175 2 3048 0 American D r Halsey , O R9734 8 1227618456580-147.4- D Willamett e Rive r Permi t Modificatio n Applicatio n Number : 95934 9 Dat e Received : Decembe r 22 , 201 4 NPDE S Major

- Industria l Stev e Schnurbusc h (503)378-830 6 Senio r Wate r Quality Permittin g Specialis tSummar y

Cascad e Pacifi c Pulp (CPP ) share s a n outfal l with neighborin g Georgi aPacifi c Halse y Mil l (GP) . CP P own s th e outfal l an di s plannin g t o relocat e th e outfal l abou t 130 0 fee t downstrea mfro mth e existin g outfal l location . The y ar e movin g th e outfal l becaus e alarg e grave l ba r ha s forme d immediatel y upstrea mfromth e curren t locatio n an di s preventin g th e effluent fromrapidl y mixin g wit h th e river . Th e ne w outfal l i s bein g move dt o adeepe r locatio n i n th e rive r

with highe r

strea mvelocities . Th e outfal l wil l consis t

o f a100-foo t

multipor t diffuser with 2 0 equall y space ddiffusers . Th e combinatio n o f

th e ne w locatio n with th e diffuser desig n wil l promot e rapi dmixin g o f th e effluent wit h th e river . DE Q i s proposin g t o modif y th e permi t

t o incorporat e th e locatio n o f th e ne w outfall . Th e permi t modificatio n i s limite dt o tw o changes : 1 . Th e locatio n o f

th e outfal l wil l chang e fro mrive r mil e 147. 7 t o rive r

mil e 147.4 . 2 . Th e length o f

th e zon e o f

initia l dilutio n (ZID ) wil l b e reduce dfrom2 2 fee t t o 1 5 feet an dth e mixin g zon e length wil l b e reduce dfrom30 0 feet t o 4 0 feet . N o othe r change s are bein g mad e t o th e permit . Comment s regardin g this permi t modificatio n ar e limite dt o th e tw o change s liste dabove . Discussio n Th e Cascad e Pacifi c Pul p mil l i s locate djus t wes t o f th e tow n o f

Halsey . I t

sit s adjacen t

t o th e Georgi aPacifi c Halse y mill . It i s a n integrate dKraf

t proces s pul p mil l tha t

produce s bleache d an dunbleache dpul p for

sale . Th e facility consist s o f apul p mill , chlorin e dioxid e generator , powe r an drecovery , recausticizin g process , wate r treatmen t

an dwastewate r

treatment . Pul p i s produce dfro mDougla s fir woo dchips . Th e wastewate r generate ddurin g th e pul p productio n proces s i s treate db y primar y clarificatio n followe db y biologica l treatmen t i n tw o larg e aerate d stabilizatio n basins . Th e effluent i s combine dwith neighborin g G P Halse y an dcurrentl y i s discharge dt o th e Willamett e Rive r a t rive r mil e 147. 7 throug h CPP' s outfall . CP P i s requestin g thei r

permi t b e modifie dt o reflec t

change s t o thei r

outfal l location . CP P i s proposin g t o mov e i t

downstrea mbecaus e o f

agrave l ba r

tha t ha s forme dupstrea mo f

th e existin g outfall . Figur e 1 show s a n aeria l phot o o f

th e rive r with th e locatio n an dsiz e o f th e grave l bar i n 200 6 compare dto 2014 . Th e grave l ba r ha s increase di n siz e an di s no w preventin g th e rive r fromrapidl y mixin g with th e effluent durin g lo w rive r

flo w conditions . Th e existin g diffuse r i s a104.5-foo t

multi-port

diffuser with 1 9 operatin g ports .

PAG E 2• s -:«: a > -^ - ,7 1 Figure I: 2006

Aerial Photo and

2014 Aerial

Photo (source: Google Earth) CP P hire daconsultan t

t o performamixin g zon e stud y wit h th e primar y objectiv e o f findin g a ne w outfal l locatio n t o promot e bette r mixing . Strea mdepth an dvelocit y measurement s wer e take n a t variou s transect s downstrea mo f th e existin g outfall . Thi s dat ai s illustrate dgraphicall y i n Figur e 2 . Th e figure clearl y show s th e lo w strea mvelocit y a t th e existin g diffuse

r location . Th e fieldstud y als o indicate dth e rive r curren t a t th e existin g locatio n wa s swirlin g an deddy

like . Figur e 2 indicate s fou r alternat e site s for

th e outfall . CP P chos e sit e D t o locat e thei r ne w outfal l (rive r

mil e 147.4) . Sit e D wa s chose n becaus e th e rive r i s deeper , experience s highe r strea mvelocitie s an di s wel l downstrea m fromth e influenc e o f

th e grave l bar . Th e propose ddiffuser

i s simila r i n length t o th e existin g one . I t

i s 10 0 feet

lon g wit h 2 0 duckbil l port s equall y space dalon g th e diffuse r line . Th e port s are pointe d downstrea mi n a"fanned " orientatio n t o optimiz e mixin g (se e Figur e 3) . Th e combine ddischarg e o f

GP andCP P throug h th e propose ddiffuser

wa s modele dusin g th e mixin g zon e software CORMI X v9.0 . Th e mode l predict s rapi dmixin g o f th e effluent immediatel y downstrea mo f th e diffuser . Becaus e o f

th e rapi dmixing , DE Q i s proposin g t o reduc e th e length o f th e ZI D an dth e siz e o f

th e mixin g zone . Th e lengt h i s bein g reduce ds o that

th e dilutio n a

t th e regulatory boundary (e.g . ZID ) matche s wha t wa s achieve dwit h th e existin g diffuse r a s determine ddurin g th e previou s permi t renewal . Th e existin g diffuse r achieve da dilutio n o f

abou t 4 7 a t th e ZI D (2 2 feet downstream) . Th e propose ddiffuse r achieve s adilutio n o f

4 7 a t adistanc e o f

1 5 ID»5WYJimMI5l. l 5iIte3Q 1 Pratond.ORiWMSUS

A 

## A Citj vS*atiAiii_ti^i» 1 t j rfcTuKoi O ^HWH ) Figure 2; Bathymetry Field Study Data (Source: MixZon) PAG E 3Unidirectiona l Perpendicula rFanned-Ou t Desig n {Ho i t o Scale ] Pla n Vie w

U a(m/s l Sid e Vie w

Figure 3: Diffuser

Orientation feet downstream . DE Q i s proposin g t o reduc e th e ZI D from2 2 fee t

t o 1 5 feet . Th e existin g diffuser achieve dadilutio n o f

abou t 8 5 a t th e edg e o f

th e 30 0 foo t mixin g zone . Th e propose ddiffuser achieve s th e sam e dilutio n a t adistanc e o f

4 0 feet downstream . DE Q i s proposin g t o reduc e th e mixin g zon e distanc e from30 0 fee t t o 4 0 feet . Thi s greatl y reduce s th e siz e o f mixin g zon e an dth e are a potentiall y impacte db y th e discharge . Movin g th e outfal l downstrea mals o prevent s elevate deffluent concentration s fro moccurrin g a t th e mout h o f

th e sloug h jus t

upstrea mfro mth e existin g outfall . Nativ e fis h hav e bee n documente di n this sloug h a s i t provide s goo dhabita t

fo r them . Movin g th e outfal l downstrea mwil l ensur e thi s critica l habita t i s no t impacte db y th e discharge . Tabl e 1 belo w list s dilutio n values for

th e variou s critica l flo w scenario s tha t ar e achieve db y th e diffuser . Table 1: Dilution Values

* . 1* »

U ' l \cut e

broni c I luma n Health

- > n carcinoge n I I uman Health - carcinoge n ZI D

Mixin g Zon e Mixin g Zon e 4 7

8 5 9 4 Mixin g Zon e 19 3

PAG E 4