# r


# •

Reply To UNITE!) " rATES ENVIRONMENTAL PROTECTIOr.

..... ENCY REGION 10 1200 Sixth Avenue Seattle, WA 981 01



# Attn Of: OW

- 130 

# AlIG 2 2 

# lom

MEMORANDUM


# SUBJECT:

FROM:

TO: Development of Limits on BODS in Westward Seafoods' NPDES Permit
Burney Hill

# ~~**\~** Aquatic Environmental Scientist
Administrative Record NPDES Permit No. AK

- 004978

- 6

EPA has determined to increase the average monthly limit (AML ) and maximum daily limit (MDL ) for five

- day biochemical oxygen demand ( BODS ) on the permitted discharge of Westward Seafoods to Captains Bay in its 2001 re
- issuance as follows:

1993 Limits 2001 Limits AML 58,000 83,028 MDL 90,000 126,825 lbs BODS / day lbs BODS / day
EPA has consulted with Westward Seafoods and its consultants, CH2M

- Hill and gmc, in a reiteration of the WASP model of Westward's discharges of BODS to Captains Bay and the effect of such discharges on level of dissolved oxygen ( D.O.)in the surface waters of the bay. Westward Seafoods presented water quality monitoring data of the levels of D.O

. in Captains Bay which demonstrate that the criteria for D.O. in Alaska Water Quality Standard has been protected during the seven years of monitoring. Westward requested that EPA work with the permittee and its consultants to revisit the design of the WASP model and the assumptions applied therein to determine if the waste load could be increased to alleviate some of the burden of barging seafood processing effluent for discharge in outer Unalaska Bay ( at a cost exceeding $3,000 / day )

. After a substantial amount of additional modeling, data analysis, and review, EPA agreed that the assumption pertaining to the wasteload of BODS discharged during 1992, the year of water quality violations that caused EPA to modify the 1991 NPDES permit and impose limits of the discharge of BODS. In brief, EPA agreed that the discharge of 

# A4-



# o Prfnted on Recycled Paper

# 2



# the "stickwater" component of the effluent commingled with the larger vc;;Lume of process effluent to impose a biochemical oxygen demand on the dissolved oxygen of the upper water column through the pycnocline. Thus, the original modeling of the effect of BODS discharge on ambient D.O. was over-estimated and the increase in the estimate of the original wasteload produced an concomitant increase in the capacity of Captains Bay to receive a BODS discharge without experiencing a violation of the standard.
Westward's consultants (Costa and Wilson, 4/11/00, 3/6/00,and 10/25/99) developed a series of WASP simulations designed to test and refine a number of key coefficients characterizing the bay**tow~rds** 

# producing the minimum levels of D.O. measured in WASP model cells 26 (surface layer of station #6) and 76 (pycnocline layer of station #6). The Westward team focused upon the vertical diffusion coefficient (Kv) 

# and the deoxygenation coefficient (Knc) , 

# and developed six alter coefficient pairs that produced model results comparable to the minimum levels of dissolved oxygen measured by the permittee in Captains Bay on 8/22/92 and 9/7/92. Costa and Wilson provided the following information in Table 3 - "Summary of Calibration Results" and Table 5 - "Summary of Model Results," to which I have added the average of the actual minima D.O. measurements of 8/22/92 and 9/7/92. Summary of Calibration and Modeling Results
Case Kv K DO 

### Actual Simulated 

### Actual Simulated Loading D0 76 D0 76 DO Z6 D0 26 

### BODzo 

### 1 0.00001 0.0036 3.1 3.1 6.8 8.76 90,500 

## 2 0.00005 0.0122 

### 3.1 3.1 6.8 6.64 1.20,233


### 3 0.00010 0.0220 3.1 3.1 6.8 5.55 122,159
4 0.00100 0.2585 3.1 3.1 6.8 4.00 115,949 5 0.00200 0.5672 3.1 3.1 6.8 3.78 113,461
6 0.01000 4.0320 3.1 3.1 6.8 3.05 111,200



# I selected calibration case 2 as most closely simulating the measurements in both WASP cells 76 and 26 on 8/22/92 and 9/7/92. This specific simulation model was subsequently run to evaluate the threshold wasteload which would reduce D.O. levels to the 5 mg/L criteria of the Alaska Water Quality Standards for estuarine waters; WASP determines 120,233 pounds of BOD" (91,781 lbs BODs = 

# 120,233 1bs BOD 2o / 

# 1.31 BOD 2o 

# :BOD s ). I then · 

# ,

# 3


# imposed a 10 % margin of safety and re
- defined an interim waste10ad allocation of 83,603 1bs BOD s
. Using my spreadsheet for developing permit limits based upon waste10ad allocations, I determined that the average monthly limit should be 83,028 1bs BODs 

# and the maximum daily limit should be 126,825 lbs BODs. 

# This determination is based upon the coefficient of variation ( ev ) of 0.26 used in the 1993 fact sheet, an effluent monitoring frequency of nine samples per month ( 2 / week ) , and EPA's standard probability percentiles for LTA, AML and MDL ( see attachments )

.

# 4

### NPOES PERMIT LI MIT CALCULATIONS fo r B005 using a TMOL/WLA Basi s : 

### EPA Value for 800-20 day Loadings of 120,2331bslday , DO-cell 76 =3.1 mg/L 

### & DO-cell 26 =6

. 64 mg/L

Facility: 

### Westward Seafoods z (0.950) = 1. 645 Waterbody: 

### Captains Bay z (0.975) = 1

. 960

P ollu tant 

### BOO , 5·day z(0.990) = 2

. 326 Isis : 1 20 ,233 Ibs/d-0

.76336-0.9 = WLA = 82 ,603 Ib s/ day
Case 1 , N = 8 

### coeff. variation, CV

_ 1 = 

### 0

. 26 Var

. ac ute1 = 

### 0

.065413 toxic per iod , TP

_ 1 = 20 days Var, TP1 = 

### 0.003374 effluent samples/ mo , ES

_ 1 = 8 samples 

### Va r , ES l = 0

.008414
LTA @ 95% LTA @ 97.5% LTA @ 99%
LTA 1--> 

### 75 , 202 73 ,838 72 , 285
AML , 95% 

### 87 ,083 85,504 83,706 AML , 97

. 50/. 89,636 88,01 1 86 , 160 AML , 99% 

### 92 ,697 91,016 89,102
MO L , 95% 

### 110 ,852 1 08,642 106,552 MO L ,97

.5 0..< 

### 120 , 152 117,974 11 5,492 MO L ,99% 

### 13 1 ,943 1 29 , 550 1 26 ,825 

### Case 2, N= 9 coeH

. variation, CV

_2 = 

### 0.26 Var , acute2 = 

### 0.065413 

### toxic per iod, TP

_2 = 

### 20 days Vart TP 2 = 

### 0.003374 effluent sam ples/ mo, ES

_2 = 9 sa mp les 

### Va r , ES2 = 0

.007 483
LTA @ 95 % LTA @ 97.5 % LTA @ 99%


### lTA 2-- > 75, 202 73,838 72 ,285

AM L , 95% 

### 86 ,378 84 ,812 

### 83,028 AML,97

. S o/c 88 ,764 87 , 155 85 ,321 AML ,99% 

### 91 ,620 89 , 958 88 , 066
MO L , 95% 

### 110 ,85 2 108, 842 106,552 MO L , 97

.5 0/. 120 , 152 117,974 115 ,492 MOL , 99% 

### 131 , 943 129 , 550 

### 126 , 825
Case 3, N= 10 coeH

. var iatio n , CV

_3 = 

### 0.26 

### Va r, acute3 = 

### 0

. 0654 1 3 t ox ic per iod , TP

_3 = 

### 20 days Var, TP 3 = 0

. 003374 effl uent sa mpl es / mo, ES

_ 3 = 10 samp les 

### Var, E S3 = 0.006737
LTA@ 95% LTA @ 97.5% 

### LTA @ 99 %
LTA 2·
· > 75,2 0 2 73,838 72 ,285 AML,95 % 

### 85,784 84,228 82,457 AM L , 97

.5 "/. 88 , 03 1 86 ,435 64 ,616 AML , 99% 

### 90 ,715 89, 071 87 , 197 MOL,95% 110 ,852 108, 642 106 ,552 MOL,97

. 5o/. 120 , 152 117 , 974 115 ,492 MO L , 99% 

### 131 , 943 129,550 126 , 825

Note on Basis : (1) Costa , Steve

. and David Wi lson . May 11, 2000

. Technical Memorandum : EPA-Region 10 Captains Bay WAS P Model - Results f or I ncreased BOD Loading

. 

### C H2M·H iII and gdc, Seattle , WA. Load i ng of 1 20 ,2331bs/day 800 ·20 from Tabl e 5 , " Mod e l R es ults," page 9 of 1 0 (2) Conve rsion factor of 0.76336 for BOO·20 to BOO ·5 fro m Cope (4/29/93), EPA Fact Sheet [0.76336 = 1/1.31[ (3) Margin of safety assessed by EPA equ a l to 10 % , ergo 1 - 0.1 = 0.9 •

### CH2M-Hill Value for 800-20 day Loadings of 122,159Ibslday , 00-ce1l76 =3

. 1 mg/L 

### & 00-ce1l26 =6

. 64 mgtl

Facility: Westward Seafoods z(0.950) = 1 .645 Wate rb ody: Capt ains B ay z(0.975) = 1.960

P oll utant: BOD,5·day z(0.990) = 2.326 I sis: 1 22, 1 59 I bsld'O.76336'O.9 = WLA = 83,926 Ibs/day

Case1, N= 8 coeff. var i ation, CV

_ 1 = 0.26 Var, acute1 = 0.0654 1 3 tox i c period, TP

_ 1 = 20 days Var, TP1 = 0.00337 ' eff lu e nt samples/mo, ES_1 = 

### 8 sam ples Va r , E Sl = 0.008414
LTA @ 95% LTA @ 97.5% LTA @ 99%


### LTA1

-- > 76,407 75,021 73,443


### AM L. 95% 88,478 86,874 85,047 AM L ,97.5°;' 91,072 89,421 87,540 

### AM L ,99% 94,182 92,474 90,529 

### MOL,95% 112 ,628 11 0,586 108,259 MOL ,97.50/. 122 ,077 119,863 1 1 7,342 MOL ,99% 134,056 131,626 128 , 857 

### Case 2 , N= 9 coeff. var i ation, CV_2 

### = 0.26 Var, acute2 = 0.0654 1 3 toxic period, TP _2 = 20 days Va r , TP 2 

### = 0.003374 effluent samples/m o, ES_2 = 

### 9 samp l es Var, E S2 = 0.007483


### LTA@ 95% LTA @ 97.5% LTA @ 99%


### LTA2-

-> 76,407 75,021 73, 443



### AM L ,95% 87,762 86, 1 71 

### 84,358 A ML ,97.50/. 90, 1 86 88,55 1 86,688 

### A ML ,99% 93,087 9 1 ,399 89,477 

### MOL,95 % 112 ,628 110,586 108 ,259 MDL,97.5 "/. 1 22,077 119,863 117,342 

### MOL,99% 1 34,056 1 31,626 

### 128,857
Case3, N= 10 cosff. varia t io n , 

### CV_3 

### = 0.26 Va r , acu t e3 

### = 0.065413 toxic p eriod, TP_3 

### = 20 days Va r , TP3 = 0.003374 effluent samples/mo, ES_3 

### = 

### 10 samples Var, ES3 = 0.006737


### LTA@95% LTA @ 97.5% 

### LTA@ 99%
LTA 2--> 76,407 75,021 73,443


### AM L ,95% 87,158 85,578 83,777 AM L ,97.50/. 89, 441 87,8 1 9 85,972 

### AM L ,99% 92,169 90,497 88,594 

### MOL,95% 11 2,628 110 ,586 108 ,2 59 MDL,97.5° ;' 1 22,077 11 9,863 11 7,342 

### MOL,99% 134 ,056 1 3 1 ,626 1 28,857

Note on Basis: (1) Costa, Steve, a n d D av id W il son. May 11 , 2000. Te c hni ca l M emorand um : EP A-Regio n 10 Captains B ay WASP Model- Re sults for In creased BOD Loading

. CH2M·Hili and gdc, Seattle, WA. L oadi ng of 120 , 233 l bs/day 

### 800- 20 from T a bl e 5, "M ode l Re s ults," page 9 of 10 (2) Co n ve rsio n faclor of 0.76336 for BOD ·20 10 BOD·5 from Cope 

### (4/29/93), EPA Fac l Sheet [0.76336 = 1 

### 1 1 .3 1] (3) Margin of sa fety assessed by EPA equa l to 10%, ergo 1

- 0. 1 

### = 0.9Westward Seafoods , Inc

. NPDES Permit. AI( 0049766 DMR September/OCtober 1997 Processing Plant El1Iuent

Worksheet: Final Effluent Discharge, N001 D

Parameter: 800 5.()AY Comparison 01 laboratory r&Sults : BOO 5·0AY concentrations

0

..
0'''2 ""03 

# ""'" ""07 09108 09/)0 09/11 09/13 09/" 09/15 

# "''' 09118 ",20 

### "'2> 09/22 

### ""'3 

# 0.". """ """

10'01 W02 

# '0'" WOS 10'0' 

### woe 

# "'''' lCYll lCY13 lCY15 ICY16 ICY17

av g valul Sap avg Oct avg B005@ CO< 

# m.,

930 "00 1900 2000 1300 "00 2200 1520 1250 1500 16'5 1560 1500 1550 "00

" 00 2550 "50 1200

"50 "50 

### "0 22)0 2>50 1600 2200 2350 2300 1200 "00 1800

1 ,706

1 ,637 1,817 8005 0 NTL 

# m.,

1270 1530 1700 1730 "00 1660 1800 1860 1545 1695 2250 1590 1785 1540 1795 1890 18" 2()" 1270

1835 1885

2035 1930 

# "" 2255 2070

1225 

### mo 1520

1 ,741
1,694 1,831 uncorr-GOO 

# m.,1895

3200 3650 3300 2550 3230 3162 3222 2635 

# ",..5
354. 

### 25" 3066 2660 31" 2991 4101 

# "'" 2946

3060 

### "25 1510 3920 3560 3100 4370 3954 '221 2670 "'35 2962

3,193
3,083 3,367

unear Regressions y=MuB

Where x Is ProCOO : eTE**(0 6322)~**  -20 NTL = (0

. 4I 07)u607

Where**~** Is GTE : NTL = (0

. 5175)x+853 correl" 0

.66 correl = 0

.79

c oo ell = 0

. 75

Where x Is uncorrected COO : CTE ,. (0

.6071)x-232 correll = 0

.89 SeaeOD coo-COD mO'1 ml)'l

200 1695 400 2800 425 3225 450 2850 425 2125 450 2700 375 2787 375 2847 275 2360 300 2745 300 3246 400 2298 425 2641 537 2143 540 2640 550 2441 425 3676 415 3065 375 2571

225 225 

# '" 325 S<2 BOO 

# "5 650 950 820 590 560

'63
"2 559 2835 "'00 1235 3595 299' 2300 3&15 

# "'" 32" 1850 

# "" 2<22

2 ,730

2 ,681 2 ,808 Flow MGD

2

. 55 3

. 54 3

.44 3

.35 3

." 3

. 45 3.51 

### 3'" 3

. 59 3.37 3

.75 1.91 3

. 12 3.<Xl 3

.45 3

.03 3

.46 3

.35 2.42

364 3

.09 1

. 44 3.51 3

. 19 

### 3'" 3

.66 3.74 CO< Ib'day 19 ,778 41 ,333 54 , 510 55,878 36.104 48,914 64,401 42,341 37.426 42,159 52 ,698 24 ,850 39 ,031 39 , 169 48 , 914 42 , 959 73,584 54.481 24,219

53,126 50,253 9.488 64.694 57 , 200 40,566 67,154 73,300 

### Nn. Ib'day 27 ,009 45,171 48 ,772 48,334 38.881 47,763 52,692 51,811 46,258 47,639 70,369 25,328 46 ,447 38,916 51 , 648 47 ,761 53

. 096 57.135 25.632

55,706 48,578

59.571 51,347 45,129 68,833 64,567 Predlcted ncorr-GOD

Ib'day 19,530 50,501 56,911 49,486 36,546 49,741 49,397 48,020 40 , 945 45,431 00,065 22,393 42,392 35,248 48 ,867 40 ,019 65 , 143 52 , 539 31,411

49 ,347 50 ,730 ',222 62,667 51,322 41 , 829 73.893 67,631 2

.72 52 , 175 62,863 3

.03 30,324 30,956 35.095 3.46 49 ,056 51 ,076 53,476 3.06 40,833 38 ,791 40,276

3

. 18 46 , 159 47,766 46,198

3

.21 44,355 45,824 44.452 3

. 13 49 ,014 5\,455 48,962 

### eT'

930 "00 )900 2000 )300 "00 2200 1520 1250 1500 16'5 1560 1500 1550 "00 "00 2550 "50 1200 "SO 1950 

# '" 22)0 2150 1600 2200 2350 2300 1200 1700 1600**M~ O~**  

# •• SErY= uncorr-GOD

1895 3200 3650 3300 2550 3230 3162 3222 2635 3"'5 354. 2698 3066 2680 3180 2991 4101 3

..

0 2946 3060 3625 15\0 3920 3560 3100 4370 3954 .221 2670 3435 2982

0.607050074 -232.040145 0

.798187866 191.5430468

Correl= 0.893413603 eTE COrr-COO

930 1695 1400 2800 1900 3225 2000 2850 1300 2125 1700 2780 2200 2787 1520 2847 1250 2360 1500 2745 1665 3246 1560 2296 1500 264\ 1550 2143 1700 2640 1700 2441 2550 3676 1950 3065 1200 2571 1750 2835 1950 3400 790 1235 2210 2>50 )600 2200 23SO 2300 )200 "00 )600 3595 2998 2300 3645 

### 33"" 3271 1850 2645 2m

6

.32E.()Q\ -\9

. 62\08 7

.45E-ODI

8

.63E-OOI NTL uncorr-GOO

1270 1895 1530 3200 1700 3650 1730 3300 1400 2550 1660 3230 1800 3162 1860 3222 \545 2635 1695 3045 2250 3546 1590 2698 1785 3066 1540 2680 1795 3180 1890 2991 1840 4101 2045 3480 1270 2946 1835 3060 1885 3625 2035 3920 1930 1780 2255 2OTO 1225 1770 1520 3560 3100 4370 3954 2670 3435 2982

0.405372298 437

. 8557633 0.62872913 164

. 3447508

0.792924417 NTL corr-COO

1270 1695 1530 2800 1700 3225 1730 2850 1400 2125 \660 2780 1800 2787 1860 2847 1545 2360 1695 2745 2250 3246 1590 2298 1785 2641 1540 2143 1795 2640 1890 2441 1840 3676 2045 3065 1270 2571 1835 2835 1885 3400 2035 3595 1930 1780 2255 2070 1225 1770 1520 299B 2300 '645 

# """ )8SO 2645 "22

4

. 11 E-ODI

6

. 24E'()()1

0

.790113 NTL

1270 1530 "00 

# "" "00 1660 )800 )860 1545 1695 2250 1590 

### "as 15" 

# "" 1890 1640 2""5 1270 1835 1885 2035 1930 1780 2255 2070 1225 1770 1520 

### eTE

930 "00 1900 2000 >300 "00 2200 )520 1250 1500 1685 1560 1500 1550 "00 "00 2550 1950 1200 1750 1950 2210 2150 1600 2200 2350 1200 "00 1600

5

. 17E-ODI 852.6807 5.56E'()()1 1 ,8E+OO2

7

.45E-ODI avg8005
1100 

# "" 1 BOO 1865 1350 1680 2000 1690 1398 1598 1968 1575 )64' 1545 1748 1795 2195 1998 1235 1793 1918 2123 2""0 1690 2228 2210 1213 

# "'5 1560 COD

1895 3200 3650 3300 2550 3230 3162 3222 2635 

# '''''5 354. 2696 3066 2680 3180 2991 4101 ,.80 2946 '060 '625 3920 3560 3100 4370 3954 2670 

## "''' 2982

5

.2E-ODI 56

. 63341 7

. 93E..Q01 1

.4E+002

8.9E-ODI 

## •