Regulations last checked for updates: Nov 23, 2024

Title 40 - Protection of Environment last revised: Nov 21, 2024
§ 421.20 - Applicability: description of the primary aluminum smelting subcategory.

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.

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.

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):

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
Metric units—kg/kkg of product
English units—lbs/thousand lbs of product
Fluoride2.01.0
Total Suspended solids3.01.5
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.

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

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pounds per million pounds) of paste produced
Benzo(a)pyrene0.0050.002
Antimony.263.117
Nickel.075.050
Aluminum.831.369
Fluoride8.0923.591

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

BAT Effluent Limitations

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pounds per million pounds) of anodes cast
Benzo(a)pyrene0.0070.003
Antimony.403.180
Nickel.115.077
Aluminum1.277.566
Fluoride12.4405.518

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

BAT Effluent Limitations

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pounds per million pounds) of anodes baked
Benzo(a)pyrene0.1460.067
Antimony8.3463.719
Nickel2.3781.600
Aluminum26.42011.720
Fluoride257.300114.200

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

BAT Effluent Limitations

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pounds per million pounds) of anodes baked
Benzo(a)pyrene0.0020.001
Antimony.097.043
Nickel.028.019
Aluminum.306.136
Fluoride2.9751.320

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

BAT Effluent Limitations

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pounds per million pounds) of anodes baked
Benzo(a)pyrene0.0250.011
Antimony1.409.628
Nickel.402.270
Aluminum4.4611.979
Fluoride43.44019.270

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

BAT Effluent Limitations

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pounds per million pounds) of anodes baked
Benzo(a)pyrene0.0380.018
Antimony2.197.979
Nickel.626.421
Aluminum6.9533.084
Fluoride67.71030.050

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

BAT Effluent Limitations

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pounds per million pounds) of cryolite recovered
Benzo(a)pyrene1.1810.547
Antimony420.400189.200
Cyanide157.60070.060
Nickel80.57035.030
Aluminum273.200122.600
Fluoride29,430.00013,310.000

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

BAT Effluent Limitations

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pounds per million pounds) of cryolite recovered
Benzo(a)pyrene1.1810.547
Antimony67.61030.120
Cyanide157.60070.060
Nickel19.27012.960
Aluminum214.00094.930
Fluoride2,084.000924.800

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

BAT Effluent Limitations

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly 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

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pound per million pounds) of aluminum produced from electrolytic reduction
Benzo(a)pyrene0.0280.013
Antimony1.618.721
Nickel.461.310
Aluminum5.1202.271
Fluoride49.86022.130

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

BAT Effluent Limitations

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pound per million pounds) of aluminum produced from electrolytic reduction
Benzo(a)pyrene0.0280.013
Antimony10.0604.525
Cyanide3.7711.676
Nickel1.928.838
Aluminum6.5372.933
Fluoride703.900318.500

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

BAT Effluent Limitations

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pound per million pounds) of aluminum produced from electrolytic reduction
Benzo(a)pyrene0.0280.013
Antimony1.618.721
Cyanide3.7711.676
Nickel0.461.310
Aluminum5.1202.271
Fluoride49.86022.130

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

BAT Effluent Limitations

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pound per million pounds) of aluminum produced from electrolytic reduction
Benzo(a)pyrene0.0560.026
Antimony3.2041.428
Nickel.913.614
Aluminum10.1404.499
Fluoride98.77043.830

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

BAT Effluent Limitations

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pound per million pounds) of aluminum produced from electrolytic reduction
Benzo(a)pyrene0.0450.021
Antimony2.5881.153
Nickel.738.496
Aluminum8.1943.634
Fluoride79.79035.400

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

BAT Effluent Limitations

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pound per million pounds) of aluminum produced from electrolytic reduction
Benzo(a)pyrene( 1)( 1)
Antimony5.0362.244
Nickel1.435.965
Aluminum15.9407.071
Fluoride155.30068.880

1 There shall be no discharge allowance for this pollutant.

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

BAT Effluent Limitations

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pound per million pounds) of aluminum produced from electrolytic 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

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pound per million pounds) of aluminum product from direct chill casting
Benzo(a)pyrene( 1)( 1)
Antimony2.5651.143
Nickel.731.492
Aluminum8.1203.602
Fluoride79.08035.090

1 There shall be no discharge allowance for this pollutant.

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

BAT Effluent Limitations

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly 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
Fluoride6.1882.746

1 There shall be no discharge allowance for this pollutant.

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

BAT Effluent Limitations

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly 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.

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

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly 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

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pound per million pounds) of anodes cast
Benzo(a)pyrene0.0070.003
Antimony.403.180
Nickel.115.077
Aluminum1.277.566
Fluoride12.4405.518
Oil and grease2.0902.090
Total suspended solids3.1352.508
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

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly 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

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pound per million pounds) of cryolite recovered
Benzo(a)pyrene1.1810.547
Antimony420.400189.200
Cyanide157.60070.060
Nickel80.57035.030
Aluminum273.200122.600
Fluoride29,430.00013,310.000
Oil and grease350.300350.300
Total suspended solids2,172.000945.800
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

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pound per million pounds) of cryolite recovered
Benzo(a)pyrene1.1810.547
Antimony67.61030.120
Cyanide157.60070.060
Nickel19.27012.960
Aluminum214.00094.930
Fluoride2,084.000924.800
Oil and grease350.300350.300
Total suspended solids2,172.000945.800
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

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pound per million pounds) of aluminum produced from electrolytic reduction
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.

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

NSPS

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pound per million pounds) of aluminum produced from electrolytic reduction
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.

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

NSPS

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pound per million pounds) aluminum produced from electrolytic reduction
Benzo(a)pyrene0.0450.021
Antimony2.5881.153
Nickel.738.496
Aluminum8.1943.634
Fluoride79.79035.400
Oil and grease13.41013.410
Total suspended solids20.12016.090
pH( 1)( 1)

1 Within the range of 7.0 to 10.0 at all times.

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

NSPS

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pound per million pounds) of aluminum produced from electrolytic reduction
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.

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

NSPS

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pound per million pounds) of aluminum produced from electrolytic reduction
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.

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

NSPS

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pound per million pounds) of aluminum product from direct chill casting
Benzo(a)pyrene( 1)( 1)
Antimony2.5651.143
Nickel.731.492
Aluminum8.1203.602
Fluoride79.08035.090
Oil and grease13.29013.290
Total suspended solids19.94015.950
pH( 2)( 2)

1 There shall be no discharge allowance for this pollutant.

2 The pH shall be maintained within the range of 7.0 to 10.0 at all times except for those situations when this waste is discharged separately and without commingling with any other waste-water in which case the pH shall be within the range of 6.0 to 10.0 at all times.

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

NSPS

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly 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
Fluoride6.1882.746
Oil and grease1.0401.040
Total suspended solids1.5601.248
pH( 2)( 2)

1 There shall be no discharge allowance for this pollutant.

2 Within the range of 7.0 to 10.0 at all times.

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

NSPS

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pounds 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
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.

[49 FR 8792, Mar. 8, 1984; 49 FR 26739, June 29, 1984, as amended at 52 FR 25558, July 7, 1987]
§ 421.25 - [Reserved]
§ 421.26 - Pretreatment standards for new sources.

Except as provided in 40 CFR 403.7, any new source subject to this subpart which introduces pollutants into a publicly owned treatment works must comply with 40 CFR part 403 and achieve the following pretreatment standards for new sources. The mass of wastewater pollutants in primary aluminum process wastewater introduced into a POTW shall not exceed the following values:

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

PSNS

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pounds per million pounds) of paste produced
Benzo(a)pyrene.000
Nickel.000.000
Fluoride.000.000

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

PSNS

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pounds per million pounds) of anodes cast
Benzo(a)pyrene0.0070.003
Nickel.115.077
Fluoride12.4405.518

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

PSNS

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pounds per million pounds) of anodes baked
Benzo(a)pyrene.000
Nickel.000.000
Fluoride.000.000

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

PSNS

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pounds per million pounds) of cryolite recovered
Benzo(a)pyrene1.1810.547
Cyanide157.60070.060
Nickel80.57035.030
Fluoride29,430.00013,310.000

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

PSNS

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pounds per million pounds) of cryolite recovered
Benzo(a)pyrene1.1810.547
Cyanide157.60070.060
Nickel19.27012.960
Fluoride2,084.000924.800

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

PSNS

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pounds per million pounds) of aluminum produced from electrolytic reduction
Benzo(a)pyrene.000
Nickel.000.000
Fluoride.000.000

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

PSNS

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pounds per million pounds) of aluminum produced from electrolytic reduction
Benzo(a)pyrene.000
Nickel.000.000
Fluoride.000.000

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

PSNS

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pounds per million pounds) of aluminum produced from electrolytic reduction
Benzo(a)pyrene0.0450.021
Nickel.738.496
Fluoride79.79035.400

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

PSNS

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pounds per million pounds) of aluminum produced from electrolytic reduction
Benzo(a)pyrene.000
Nickel.000.000
Fluoride.000.000

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

PSNS

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pounds per million pounds) of aluminum produced from electrolytic reduction
Benzo(a)pyrene.000
Nickel.000.000
Fluoride.000.000

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

PSNS

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pounds per million pounds) of aluminum product from direct chill casting
Benzo(a)pyrene( 1)( 1)
Nickel.731.492
Fluoride79.08035.090

1 There shall be no discharge allowance for this pollutant.

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

PSNS

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pound per million pounds) of aluminum product from rod casting
Benzo(a)pyrene( 1)( 1)
Nickel.057.038
Fluoride6.1882.746

1 There shall be no discharge allowance for this pollutant.

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

PSNS

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pound per million pounds) of aluminum product from stationary casting or shot casting
Benzo(a)pyrene.000
Nickel.000.000
Fluoride.000.000
[49 FR 8792, Mar. 8, 1984; 49 FR 26739, June 29, 1984, as amended at 52 FR 25559, July 7, 1987]
§ 421.27 - [Reserved]
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,c,e,and, 1316 (b) andc, 1317 (b) andc,1318; 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.
cite as: 40 CFR 421.21