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State o f Orego n Department

o f Environmental Qualit y 

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

Apri l 201 5 

## Orego n Departmen t

o f Environmenta l Qualit y Wester n Regio n 402 6 Fairvie 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 : Georgia-Pacifi c Consumer Product s L P P O Bo x 21 5 Halsey , O R9734 8 Fil e Number : 10581 4 Permi t Number : 10148 8 Expiratio n Date : Novembe r 30,201 5 EPA Referenc e Number : OR003340- 5 Alic e McConaugh y (541)369-158 9 3047 0 American D r Halsey , O R9734 8 1227618456580-147.4- D Willamett e Rive r Permi t Modificatio n Applicatio n Number : 95932 7 Dat e Received : January 13,201 5 NPDE S Majo r

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

Th e Georgi aPacifi c Halse y Mil l (GP ) share s a n outfal l with neighborin g Cascad e Pacifi c Pul p (CPP) . 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 feet downstrea m fro 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 dimmediatel y upstrea mfromth e curren t locatio n an di s preventin g th e effluent fro m rapidl y mixin g with 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 effluen t 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 lengt h wil l b e reduce dfrom30 0 feet t o 4 0 feet . N o othe r change s ar e bein g mad e t o th e permit . Comment s regardin g thi s permi t modificatio n ar e limite dt o th e tw o change s liste dabove . Discussio n Th e GP Halse y 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 Cascad e Pacifi c Pulp mill . I t

consist s o f

apape r mill , aconvertin g operation , an dasecondary fibe r recyclin g plan t

with a n activate dsludg e wastewate r treatmen t

system . Th e facility produce s paper , whic h i s converte dint o tissu e an dtowels . Th e finishe dproduc t i s package dan dshippe d fo r sal e t o commercial , retai l an dwholesal e markets . Th e produc t mi x an dconstituent s var y base do n custome r

an dmarke t

demands . Th e facility i s segregate dint o proces s buildings , whic h consis t o f th e Pape r Mill , Convertin g Area , Maintenanc e Area , Secondary Fibe r an dWastewate r Treatment . Th e effluent

i s combine dwit h neighborin g Cascad e Pacifi c Pul p an dcurrentl y i s discharge dt o th e Willamett e Rive r a t river mil e 147. 7 throug h Cascad e Pacific' s outfall . G P Halse y i s requestin g thei r permi t b e modifie dt o reflec t

change s t o thei r

outfal l location . CPP own s th e outfal l an di s proposin g t o mov e i t downstrea mbecaus e o f

agrave l ba

r tha t ha s forme d upstrea mo f

th e existin g outfall . Figur e 1 show s a n aerial phot o o f th e rive r with th e locatio n an d siz e o f th e grave l ba

r i n 200 6 compare dt o 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 wit h 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-por t

diffuse r with 1 9 operatin g ports .

PAG E 2Figure 1: 2006 Aerial Photo and

2014 Aerial

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

consultan t

t o performamixin g zon e stud y wit h th e primar y objectiv e o f findin g ane 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 figur e clearl y show s th e lo w strea mvelocit y a t th e existin g diffuser

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 four 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 mfromth e influenc e o f th e grave l bar . Th e propose ddiffuser

i s similar

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

i s 10 0 fee t

lon g wit h 2 0 duckbil l port s equall y space dalon g th e diffuser line . Th e port s ar e 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 an dCPP throug h th e propose ddiffuser

wa s modele dusin g th e mixin g zon e software CORMIXv9.0 . 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 lengt h o f th e ZI D an dth e siz e o f

th e mixin g zone . Th e length i s bein g reduce ds o tha t

th e dilutio n a

t th e regulator y boundar y (e.g . ZID ) matche s wha t wa s achieve dwit h th e existin g diffuser a s determine ddurin g th e previou s permi t renewal . Th e existin g diffuser 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 Mlx^a n lOMSWWmfflSl . SUI 6 3Q 1 PwUand , O R 9720 5 US A M i man inj j 

## A Of/y i Inf f Jili t tir& M Csritrat l ^fln ? lH*RMJ Figure 2: Bathymetry Field Study Data (Source: MixZon) PAG E 3Unidirectiona l Perpendicula rFanned-Ou t Desig n (H « lo Sols )

Pla n Via w

Ua (m/s ) Sid e Vie w

Figure 3: Diffuser

Orientation achieve s adilutio n o f 4 7 a t adistanc e o f

1 5 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 diffuse r achieve dadilutio n o f

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

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

4 0 fee t downstream . DE Q i s proposin g t o reduc e th e mixin g zon e distanc e from30 0 feet 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 fromoccurrin g a t th e mout h o f

th e sloug h jus t

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

for 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 \sut e

f ironi c 1 1 uma n Healt h — I I > n carcinoge n 1 1 uma n Healt h - carcinoge n ZI D

Mixin g Zon e Mixin g Zon e Mixin g Zon e 4 7

8 5 9 4 19 3

PAG E 4