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National
United States Regulations
40 CFR PART 421—NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY



PART 421—NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY




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Authority: Secs. 301, 304 (b), (c), (e), and (g), 306 (b) and (c), 307 (b) and (c), 308 and 501 of the Clean Water Act (the Federal Water Pollution Control Act Amendments of 1972, as amended by the Clean Water Act of 1977) and the Water Quality Act of 1987 (the “Act”); 33 U.S.C. 1311, 1314 (b), (c), (e), and (g), 1316 (b) and (c), 1317 (b) and (c), 1318 and 1361; 86 Stat. 816, Pub. L. 92–500; 91 Stat. 1567, Pub. L. 95–217; 101 Stat. 7, Pub. L. 100–4.

Source: 49 FR 8790, Mar. 8, 1984, unless otherwise noted.

General Provisions
top
§ 421.1 Applicability.
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This part applies to facilities producing primary metals from ore concentrates and recovering secondary metals from recycle wastes which discharge or may discharge pollutants to waters of the United States or which introduce or may introduce pollutants into a publicly owned treatment works. The applicability of this part to alloying or casting of nonferrous metals is limited to alloying or casting of hot metal directly from the nonferrous metals manufacturing process without cooling. Remelting followed by alloying or cooling is included in the aluminum forming, nonferrous metals forming, or metal molding and casting point source categories.

§ 421.2 [Reserved]
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§ 421.3 Monitoring and reporting requirements.
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The following special monitoring requirements apply to all facilities controlled by this regulation:

(a) The monthly average regulatory values shall be the basis for the monthly average discharge in direct discharge permits and for pretreatment standards. Compliance with the monthly discharge limit is required regardless of the number of samples analyzed and averaged.

(b) Periodic analysis for cyanide are not required for a facility in the primary beryllium subcategory (subpart O of this part) when both of the following conditions are met:

(1) The first wastewater sample taken in each calandar year has been analyzed and found to contain less than 0.07 mg/1 cyanide.

(2) The owner or operator of the primary beryllium manufacturing facility certifies in writing to the POTW authority or permit issuing authority that cyanide is neither generated nor used in the beryllium manufacturing process employed at that facility.

[49 FR 8790, Mar. 8, 1984, as amended at 55 FR 31697, Aug. 3, 1990]

§ 421.4 Compliance date for pretreatment standards for existing sources (PSES).
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The PSES compliance deadline in subparts A through M is March 8, 1987. The PSES compliance deadline for plants in subparts N through AE is September 20, 1988.

[50 FR 52776, Dec. 26, 1985]

§ 421.5 Removal allowances for pretreatment standards.
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Removal allowances pursuant to 40 CFR 403.7(a) may be granted for the toxic metals limited in 40 CFR part 421 when used as indicator pollutants.

Subpart A—Bauxite Refining Subcategory
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§ 421.10 Applicability; description of the bauxite refining subcategory.
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The provisions of this subpart are applicable to discharges resulting from the refining of bauxite to alumina by the Bayer process or by the combination process.

[39 FR 12825, Apr. 8, 1974]

§ 421.11 Specialized definitions.
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For the purpose of this subpart:

(a) Except as provided below, the general definitions, abbreviations and methods of analysis set forth in part 401 of this chapter shall apply to this subpart.

(b) The term bauxite shall mean ore containing alumina monohydrate or alumina trihydrate which serves as the principal raw material for the production of alumina by the Bayer process or by the combination process.

(c) The term product shall mean alumina.

(d) For all impoundments the term within the impoundment for purposes of calculating the volume of process wastewater which may be discharged, shall mean the surface area within the impoundment at the maximum capacity plus the area of the inside and outside slopes of the impoundment dam and the surface area between the outside edge of the impoundment dam and seepage ditches upon which rain falls and is returned to the impoundment. For the purpose of such calculations, the surface area allowance for external appurtenances to the impoundment shall not be more than 30 percent of the water surface area within the impoundment dam at maximum capacity.

(e) The term pond water surface area for the purpose of calculating the volume of waste water shall mean the area within the impoundment for rainfall and the actual water surface area for evaporation.

[39 FR 12825, Apr. 8, 1974, as amended at 40 FR 48348, Oct. 15, 1975]

§ 421.12 Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available.
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Except as provided in 40 CFR 125.30 through 125.32, any existing point source subject to this subpart, shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available:

(a) Subject to the provisions of paragraph (b) of this section, the following limitations establish the quantity or quality of pollutants or pollutant properties which may be discharged by a point source subject to the provisions of this subpart after application of the best practicable control technology currently available: There shall be no discharge of process waste water pollutants to navigable waters.

(b) During any calendar month there may be discharged from the overflow of a process waste water impoundment either a volume of process waste water equal to the difference between the precipitation for that month that falls within the impoundment and the evaporation within the impoundment for that month, or, if greater, a volume of process waste water equal to the difference between the mean precipitation for that month that falls within the impoundment and the mean evaporation for that month as established by the National Climatic Center, National Oceanic and Atmospheric Administration, for the area in which such impoundment is located (or as otherwise determined if no monthly data have been established by the National Climatic Center).

[39 FR 12825, Apr. 8, 1974, as amended at 50 FR 38342, Sept. 20, 1985]

§ 421.13 Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best available technology economically achievable.
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Except as provided in 40 CFR 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best available technology economically achievable:

(a) Subject to the provisions of paragraph (b) of this section, the following limitations establish the quantity or quality of pollutants or pollutant properties which may be discharged by a point source subject to the provisions of this subpart after application of the best available technology economically achievable: There shall be no discharge of process waste water pollutants to navigable waters.

(b) During any calendar month there may be discharged from the overflow of a process waste water impoundment either a volume of process waste water equal to the difference between the precipitation for that month that falls within the impoundment and the evaporation within the impoundment for that month, or, if greater, a volume of process waste water equal to the difference between the mean precipitation for that month that falls within the impoundment and the mean evaporation for that month as established by the National Climatic Center, National Oceanic and Atmospheric Administration, for the area in which such impoundment is located (or as otherwise determined if no monthly data have been established by the National Climatic Center).

[39 FR 12825, Apr. 8, 1974, as amended at 50 FR 38342, Sept. 20, 1985]

§ 421.14 [Reserved]
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§ 421.15 Standards of performance for new sources.
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(a) Subject to the provisions of paragraph (b) of this section, the following standards of performance establish the quantity or quality of pollutants or pollutant properties which may be discharged by a new source subject to the provisions of this subpart: There shall be no discharge of process waste water pollutants to navigable waters.

(b) During any calendar month there may be discharged from the overflow of a process waste water impoundment either a volume of process waste water equal to the difference between the precipitation for that month that falls within the impoundment and the evaporation within the impoundment for that month, or, if greater, a volume of process waste water equal to the difference between the mean precipitation for that month that falls within the impoundment and the mean evaporation for that month as established by the National Climatic Center, National Oceanic and Atmospheric Administration, for the area in which such impoundment is located (or as otherwise determined if no monthly data have been established by the National Climatic Center).

[39 FR 12825, Apr. 8, 1974]

§ 421.16 Pretreatment standards for new sources.
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Any new sources subject to this subpart which introduces pollutants into a publicly owned treatment works must comply with 40 CFR part 403.

[50 FR 38342, Sept. 20, 1985]

Subpart B—Primary Aluminum Smelting Subcategory
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§ 421.20 Applicability: description of the primary aluminum smelting subcategory.
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The provisions of this subpart are applicable to discharges resulting from the production of aluminum from alumina in the Hall-Heroult process.

§ 421.21 Specialized definitions.
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For the purpose of this subpart:

(a) Except as provided below, the general definitions, abbreviations and methods of analysis set forth in part 401 of this chapter, shall apply to this subpart.

(b) The term product shall mean hot aluminum metal.

(c) If a permittee chooses to analyze for benzo(a)pyrene using any EPA-approved method, any “non-detected” measurements shall be considered zeroes for the purpose of determining compliance with this regulation.

[49 FR 8792, Mar. 8, 1984, as amended at 52 FR 25556, July 7, 1987]

§ 421.22 Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available.
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Except as provided in 40 CFR 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable technology currently available (BPT):



------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
Metric
units_kg/
kkg of
product
English
units_lbs/
thousand
lbs of
product
-------------------------
Fluoride...................................... 2.0 1.0
Total Suspended solids........................ 3.0 1.5
pH............................................ (\1\) (\1\)
------------------------------------------------------------------------
\1\ Within the range of 6 to 9 at all times.


[49 FR 8792, Mar. 8, 1984; 49 FR 29794, July 24, 1984]

§ 421.23 Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best available technology economically achievable.
top
Except as provided in 40 CFR 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best available technology economically achievable:

(a) Subpart B—Anode and Cathode Paste Plant Wet Air Pollution Control


BAT Effluent Limitations
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pounds per
million
pounds) of
paste
produced
-------------------------
Benzo(a)pyrene................................ 0.005 0.002
Antimony...................................... .263 .117
Nickel........................................ .075 .050
Aluminum...................................... .831 .369
Fluoride...................................... 8.092 3.591
------------------------------------------------------------------------


(b) Subpart (B)—Anode Contact Cooling and Briquette Quenching.


BAT Effluent Limitations
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pounds per
million
pounds) of
anodes cast
-------------------------
Benzo(a)pyrene................................ 0.007 0.003
Antimony...................................... .403 .180
Nickel........................................ .115 .077
Aluminum...................................... 1.277 .566
Fluoride...................................... 12.440 5.518
------------------------------------------------------------------------


(c) Subpart (B)—Anode Bake Plant Wet Air Pollution Control (Closed Top Ring Furnace).


BAT Effluent Limitations
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pounds per
million
pounds) of
anodes
baked
-------------------------
Benzo(a)pyrene................................ 0.146 0.067
Antimony...................................... 8.346 3.719
Nickel........................................ 2.378 1.600
Aluminum...................................... 26.420 11.720
Fluoride...................................... 257.300 114.200
------------------------------------------------------------------------


(d) Subpart B—Anode Bake Plant Wet Air Pollution Control (Open Top Ring Furnace With Spray Tower Only).


BAT Effluent Limitations
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pounds per
million
pounds) of
anodes
baked
-------------------------
Benzo(a)pyrene................................ 0.002 0.001
Antimony...................................... .097 .043
Nickel........................................ .028 .019
Aluminum...................................... .306 .136
Fluoride...................................... 2.975 1.320
------------------------------------------------------------------------


(e) Subpart B—Anode Bake Plant Wet Air Pollution Control (Open Top Ring Furnace With Wet Electrostatic Precipitator and Spray Tower).


BAT Effluent Limitations
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pounds per
million
pounds) of
anodes
baked
-------------------------
Benzo(a)pyrene................................ 0.025 0.011
Antimony...................................... 1.409 .628
Nickel........................................ .402 .270
Aluminum...................................... 4.461 1.979
Fluoride...................................... 43.440 19.270
------------------------------------------------------------------------


(f) Subpart B—Anode Bake Plant Wet Air Pollution Control (Tunnel Kiln).


BAT Effluent Limitations
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pounds per
million
pounds) of
anodes
baked
-------------------------
Benzo(a)pyrene................................ 0.038 0.018
Antimony...................................... 2.197 .979
Nickel........................................ .626 .421
Aluminum...................................... 6.953 3.084
Fluoride...................................... 67.710 30.050
------------------------------------------------------------------------


(g) Subpart B—Cathode Reprocessing (Operated With Dry Potline Scrubbing and Not Commingled With Other Process or Nonprocess Waters).


BAT Effluent Limitations
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pounds per
million
pounds) of
cryolite
recovered
-------------------------
Benzo(a)pyrene................................ 1.181 0.547
Antimony...................................... 420.400 189.200
Cyanide....................................... 157.600 70.060
Nickel........................................ 80.570 35.030
Aluminum...................................... 273.200 122.600
Fluoride...................................... 29,430.000 13,310.000
------------------------------------------------------------------------


(h) Subpart B—Cathode Reprocessing (Operated With Dry Potline Scrubbing and Commingled With Other Process or Nonprocess Waters).


BAT Effluent Limitations
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pounds per
million
pounds) of
cryolite
recovered
-------------------------
Benzo(a)pyrene................................ 1.181 0.547
Antimony...................................... 67.610 30.120
Cyanide....................................... 157.600 70.060
Nickel........................................ 19.270 12.960
Aluminum...................................... 214.000 94.930
Fluoride...................................... 2,084.000 924.800
------------------------------------------------------------------------


(i) Subpart B—Cathode Reprocessing (Operated With Wet Potline Scrubbing).


BAT Effluent Limitations
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pound per
million
pounds) of
cryolite
recovered
-------------------------
Benzo(a)pyrene................................ .000 ...........
Antimony...................................... .000 .000
Cyanide....................................... .000 .000
Nickel........................................ .000 .000
Aluminum...................................... .000 .000
Fluoride...................................... .000 .000
------------------------------------------------------------------------


(j) Subpart B—Potline Wet Air Pollution Control (Operated Without Cathode Reprocessing).


BAT Effluent Limitations
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pound per
million
pounds) of
aluminum
produced
from
electrolyti
c reduction
-------------------------
Benzo(a)pyrene................................ 0.028 0.013
Antimony...................................... 1.618 .721
Nickel........................................ .461 .310
Aluminum...................................... 5.120 2.271
Fluoride...................................... 49.860 22.130
------------------------------------------------------------------------


(k) Subpart B—Potline Wet Air Pollution Control (Operated With Cathode Reprocessing and Not Commingled With Other Process or Nonprocess Waters).


BAT Effluent Limitations
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pound per
million
pounds) of
aluminum
produced
from
electrolyti
c reduction
-------------------------
Benzo(a)pyrene................................ 0.028 0.013
Antimony...................................... 10.060 4.525
Cyanide....................................... 3.771 1.676
Nickel........................................ 1.928 .838
Aluminum...................................... 6.537 2.933
Fluoride...................................... 703.900 318.500
------------------------------------------------------------------------


(l) Potline Wet Air Pollution Control Cooperated With Cathode Reprocessing and Commingled With Other Process or Nonprocess Wastewaters).


BAT Effluent Limitations
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pound per
million
pounds) of
aluminum
produced
from
electrolyti
c reduction
-------------------------
Benzo(a)pyrene................................ 0.028 0.013
Antimony...................................... 1.618 .721
Cyanide....................................... 3.771 1.676
Nickel........................................ 0.461 .310
Aluminum...................................... 5.120 2.271
Fluoride...................................... 49.860 22.130
------------------------------------------------------------------------


(m) Subpart B—Potroom Wet Air Pollution Control.


BAT Effluent Limitations
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pound per
million
pounds) of
aluminum
produced
from
electrolyti
c reduction
-------------------------
Benzo(a)pyrene................................ 0.056 0.026
Antimony...................................... 3.204 1.428
Nickel........................................ .913 .614
Aluminum...................................... 10.140 4.499
Fluoride...................................... 98.770 43.830
------------------------------------------------------------------------


(n) Subpart B—Potline SO2 Emissions Wet Air Pollution Control.


BAT Effluent Limitations
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pound per
million
pounds) of
aluminum
produced
from
electrolyti
c reduction
-------------------------
Benzo(a)pyrene................................ 0.045 0.021
Antimony...................................... 2.588 1.153
Nickel........................................ .738 .496
Aluminum...................................... 8.194 3.634
Fluoride...................................... 79.790 35.400
------------------------------------------------------------------------


(o) Subpart B—Degassing Wet Air Pollution Control.


BAT Effluent Limitations
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pound per
million
pounds) of
aluminum
produced
from
electrolyti
c reduction
-------------------------
Benzo(a)pyrene................................ (\1\) (\1\)
Antimony...................................... 5.036 2.244
Nickel........................................ 1.435 .965
Aluminum...................................... 15.940 7.071
Fluoride...................................... 155.300 68.880
------------------------------------------------------------------------
\1\ There shall be no discharge allowance for this pollutant.


(p) Subpart B—Pot Repair and Pot Soaking.


BAT Effluent Limitations
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pound per
million
pounds) of
aluminum
produced
from
electrolyti
c reduction
-------------------------
Benzo(a)pyrene................................ .000 ...........
Antimony...................................... .000 .000
Nickel........................................ .000 .000
Aluminum...................................... .000 .000
Fluoride...................................... .000 .000
------------------------------------------------------------------------


(q) Subpart B—Direct Chill Casting Contact Cooling.


BAT Effluent Limitations
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pound per
million
pounds) of
aluminum
product
from direct
chill
casting
-------------------------
Benzo(a)pyrene................................ (\1\) (\1\)
Antimony...................................... 2.565 1.143
Nickel........................................ .731 .492
Aluminum...................................... 8.120 3.602
Fluoride...................................... 79.080 35.090
------------------------------------------------------------------------
\1\ There shall be no discharge allowance for this pollutant.


(r) Subpart B—Continuous Rod Casting Contact Cooling.


BAT Effluent Limitations
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pound per
million
pounds) of
aluminum
product
from rod
casting
-------------------------
Benzo(a)pyrene................................ (\1\) (\1\)
Antimony...................................... .201 .089
Nickel........................................ .057 .038
Aluminum...................................... .636 .282
Fluoride...................................... 6.188 2.746
------------------------------------------------------------------------
\1\ There shall be no discharge allowance for this pollutant.


(s) Subpart B—Stationary Casting or Shot Casting Contact Cooling.


BAT Effluent Limitations
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pound per
million
pounds) of
aluminum
product
from
stationary
casting or
shot
casting
-------------------------
Benzo(a)pyrene................................ .000 ...........
Antimony...................................... .000 .000
Nickel........................................ .000 .000
Aluminum...................................... .000 .000
Fluoride...................................... .000 .000
------------------------------------------------------------------------


[49 FR 8792, Mar. 8, 1984, as amended at 52 FR 25556, July 7, 1987]

§ 421.24 Standards of performance for new sources.
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Any new source subject to this subpart shall achieve the following new source performance standards:

(a) Subpart B—Anode and Cathode Paste Plant Wet Air.


Pollution Control_NSPS
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pound per
million
pounds) of
paste
produced
-------------------------
Benzo(a)pyrene................................ .000 ...........
Antimony...................................... .000 .000
Nickel........................................ .000 .000
Aluminum...................................... .000 .000
Fluoride...................................... .000 .000
Oil and grease................................ .000 .000
Total suspended solids........................ .000 .000
pH............................................ (\1\) (\1\)
------------------------------------------------------------------------
\1\ Within the range of 7.0 to 10.0 at all times.


(b) Subpart B—Anode Contact Cooling and Briquette Quenching.


NSPS
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pound per
million
pounds) of
anodes cast
-------------------------
Benzo(a)pyrene................................ 0.007 0.003
Antimony...................................... .403 .180
Nickel........................................ .115 .077
Aluminum...................................... 1.277 .566
Fluoride...................................... 12.440 5.518
Oil and grease................................ 2.090 2.090
Total suspended solids........................ 3.135 2.508
pH............................................ (\1\) (\1\)
------------------------------------------------------------------------
\1\ Within the range of 7.0 to 10.0 at all times.


(c) Subpart B—Anode Bake Plant Wet Air Pollution Control.


NSPS
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pound per
million
pounds) of
anodes
baked
-------------------------
Benzo(a)pyrene................................ .000 ...........
Antimony...................................... .000 .000
Nickel........................................ .000 .000
Aluminum...................................... .000 .000
Fluoride...................................... .000 .000
Oil and grease................................ .000 .000
Total suspended solids........................ .000 .000
pH............................................ (\1\) (\1\)
------------------------------------------------------------------------
\1\ Within the range of 7.0 to 10.0 at all times.


(d) Subpart B—Cathode Reprocessing (Operated With Dry Potline Scrubbing and Not Commingled With Other Process or Nonprocess Waters).


NSPS
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pound per
million
pounds) of
cryolite
recovered
-------------------------
Benzo(a)pyrene................................ 1.181 0.547
Antimony...................................... 420.400 189.200
Cyanide....................................... 157.600 70.060
Nickel........................................ 80.570 35.030
Aluminum...................................... 273.200 122.600
Fluoride...................................... 29,430.000 13,310.000
Oil and grease................................ 350.300 350.300
Total suspended solids........................ 2,172.000 945.800
pH............................................ (\1\) (\1\)
------------------------------------------------------------------------
\1\ Within the range of 7.0 to 10.0 at all times.


(e) Subpart B—Cathode Reprocessing (Operated With Dry Potline Scrubbing and Commingled With Other Process or Nonprocess Waters).


NSPS
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly
any 1 day average
------------------------------------------------------------------------
mg/kg
(pound per
million
pounds) of
cryolite
recovered
-------------------------
Benzo(a)pyrene................................ 1.181 0.547
Antimony...................................... 67.610 30.120
Cyanide....................................... 157.600 70.060
Nickel........................................ 19.270 12.960
Aluminum...................................... 214.000 94.930
Fluoride...................................... 2,084.000 924.800
Oil and grease................................ 350.300 350.300
Total suspended solids........................ 2,172.000 945.800
pH............................................ (\1\) (\1\)
------------------------------------------------------------------------
\1\ Within the range of 7.0 to 10.0 at all times.


(f) Subpart B—Potline Wet Air Pollution Control.


NSPS
------------------------------------------------------------------------
Maximum for
Pollutant or pollutant property Maximum for monthly (continued)