Regulations last checked for updates: May 19, 2024

Title 40 - Protection of Environment last revised: May 16, 2024
§ 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]
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 421.23