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 

Aquatic 

Burney Hill 

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 KDO Actual Simulated Actual Simulated Loading 

D076 D076 DOZ6 D026 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 BOD2o / 1.31 BOD2o :BODs). I then 

· , 
3 

imposed a 10% margin of safety and re- defined an interim 

waste10ad allocation of 83,603 1bs BODs. 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 LIMIT CALCULATIONS for B005 using a TMOL/WLA Basis: 

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 

Pollutant BOO, 5·day z(0.990) = 2.326 

Isis: 120,233 Ibs/d-0.76336-0.9 = WLA = 82,603 Ibs/day 

Case1, N= 8 

coeff. variation, CV _1 = 0.26 Var. acute1 = 0.065413 

toxic period, TP _1 = 20 days Var, TP1 = 0.003374 

effluent samples/mo, ES_ 1 = 8 samples Var, ESl = 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 

MOL, 95% 110,852 108,642 106,552 

MOL,97.50..< 120,152 117,974 11 5,492 

MOL,99% 131,943 129,550 126,825 

Case 2, N= 9 

coeH. variation, CV_2 = 0.26 Var, acute2 = 0.065413 

toxic period, TP _2 = 20 days Vart TP2 = 0.003374 

effluent samples/mo, ES_2 = 9 samples Var, ES2 = 0.007483 

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

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

AML, 95% 86,378 84,812 83,028 

AML,97.So/c 88,764 87,155 85,321 

AML,99% 91 ,620 89,958 88,066 

MOL, 95% 110,852 108,842 106,552 

MOL, 97.50/. 120,152 117,974 115,492 

MOL, 99% 131 ,943 129,550 126,825 

Case3, N= 10 

coeH. variation, CV_3 = 0.26 Var, acute3 = 0.065413 

toxic period, TP _3 = 20 days Var, TP3 = 0.003374 

effluent samples/mo, ES_3 = 10 samples Var, ES3 = 0.006737 

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

LTA 2··> 75,202 73,838 72,285 

AML,95% 85,784 84,228 82,457 

AML, 97.5"/. 88,031 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 

MOL, 99% 131 ,943 129,550 126,825 

Note on Basis: (1) Costa, Steve. and David Wilson. May 11, 2000. Technical Memorandum: 

EPA-Region 10 Captains Bay WASP Model - Results for Increased BOD Loading. 

CH2M·HiII and gdc, Seattle, WA. 

Loading of 120,2331bs/day 800·20 from Table 5, "Model Results," page 9 of 10 

(2) Conversion factor of 0.76336 for BOO·20 to BOO·5 from Cope (4/29/93), EPA Fact Sheet [0.76336 = 1/1.31[ 

(3) Margin of safety assessed by EPA equal 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 

Waterbody: Captains Bay z(0.975) = 1.960 

Pollutant: BOD,5·day z(0.990) = 2.326 

Isis: 122, 159 Ibsld'O.76336'O.9 = WLA = 83,926 Ibs/day 

Case1, N= 8 

coeff. variation, CV_1 = 0.26 Var, acute1 = 0.065413 

toxic period, TP _ 1 = 20 days Var, TP1 = 0.00337' 

effluent samples/mo, ES_1 = 8 samples Var, ESl = 0.008414 

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

LTA1 --> 76,407 75,021 73,443 

AML. 95% 88,478 86,874 85,047 

AML,97.5°;' 91,072 89,421 87,540 

AML,99% 94,182 92,474 90,529 

MOL,95% 112,628 11 0,586 108,259 

MOL,97.50/. 122,077 119,863 117,342 

MOL,99% 134,056 131,626 128,857 

Case 2, N= 9 

coeff. variation, CV_2 = 0.26 Var, acute2 = 0.065413 

toxic period, TP _2 = 20 days Var, TP2 = 0.003374 

effluent samples/mo, ES_2 = 9 samples Var, ES2 = 0.007483 

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

LTA2--> 76,407 75,021 73,443 

AML,95% 87,762 86, 171 84,358 

AML,97.50/. 90, 186 88,551 86,688 

AML,99% 93,087 91,399 89,477 

MOL,95% 112,628 110,586 108,259 

MDL,97.5"/. 122,077 119,863 117,342 

MOL,99% 134,056 131,626 128,857 

Case3, N= 10 

cosff. variation, CV _3 = 0.26 Var, acute3 = 0.065413 

toxic period, TP _3 = 20 days Var, 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 

AML,95% 87,158 85,578 83,777 

AML,97.50/. 89,441 87,819 85,972 

AML,99% 92,169 90,497 88,594 

MOL,95% 11 2,628 110,586 108,259 

MDL,97.5°;' 122,077 11 9,863 117,342 

MOL,99% 134,056 131,626 128,857 

Note on Basis: (1) Costa, Steve, and David W ilson. May 11 , 2000. Technical Memorandum: 

EPA-Region 10 Captains Bay WASP Model- Results for Increased BOD Loading. 

CH2M·Hili and gdc, Seattle, WA. 

Loading of 120,233 lbs/day 800-20 from Table 5, "Model Results," page 9 of 10 

(2) Conversion faclor of 0.76336 for BOD·20 10 BOD·5 from Cope (4/29/93), EPA Facl Sheet [0.76336 = 1 1 1.31] 

(3) Margin of safety assessed by EPA equal to 10%, ergo 1 - 0.1 = 0.9 
Westward Seafoods, Inc. 

NPDES Permit. AI( 0049766 

DMR September/OCtober 1997 

Processing Plant El1Iuent 

Worksheet: Final Effluent Discharge, N 001 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 

avg 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 

80050 

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 = (0.4 I 07)u607 

Where ~ Is GTE: 

NTL = (0.5175)x+853 

correl" 0.66 

correl = 0.79 

cooell = 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 

•