Regulations last checked for updates: May 18, 2024

Title 40 - Protection of Environment last revised: May 16, 2024
§ 471.81 - Effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT).

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

(a) Rolling spent neat oils—subpart H—BPT. There shall be no discharge of process wastewater pollutants.

(b) Rolling spent emulsions.

Subpart H—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of zinc rolled with emulsions
Chromium0.00060.0003
Copper0.0030.002
Cyanide0.00040.0002
Zinc0.0020.0009
Oil and grease0.0280.017
TSS0.0570.027
pH( 1)( 1)

1 Within the range of 7.5 to 10.0 at all times.

(c) Rolling contact cooling water.

Subpart H—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of zinc rolled with contact cooling water
Chromium0.2360.0097
Copper1.020.536
Cyanide0.1560.065
Zinc0.7830.327
Oil and grease10.76.43
TSS22.010.5
pH( 1)( 1)

1 Within the range of 7.5 to 10.0 at all times.

(d) Drawing spent emulsions.

Subpart H—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of zinc drawn with emulsions
Chromium0.0030.001
Copper0.0110.006
Cyanide0.0020.0007
Zinc0.0090.004
Oil and grease0.1160.070
TSS0.2380.113
pH( 1)( 1)

1 Within the range of 7.5 to 10.0 at all times.

(e) Direct chill casting contact cooling water.

Subpart H—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of zinc cast by the direct chill method
Chromium0.2220.091
Copper0.9600.505
Cyanide0.1470.061
Zinc0.7380.308
Oil and grease10.16.06
TSS20.79.85
pH( 1)( 1)

1 Within the range of 7.5 to 10.0 at all times.

(f) Stationary casting contact cooling water—subpart H—BPT. There shall be no discharge of process wastewater pollutants.

(g) Heat treatment contact cooling water.

Subpart H—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of zinc heat treated
Chromium0.3360.138
Copper1.450.763
Cyanide0.2210.092
Zinc1.120.466
Oil and grease15.39.16
TSS31.314.9
pH( 1)( 1)

1 Within the range of 7.5 to 10.0 at all times.

(h) Surface treatment spent baths.

Subpart H—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of zinc surface treated
Chromium0.0390.016
Copper0.1690.089
Cyanide0.0260.011
Zinc0.1300.054
Oil and grease1.781.07
TSS3.641.73
pH( 1)( 1)

1 Within the range of 7.5 to 10.0 at all times.

(i) Surface treatment rinse.

Subpart H—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of zinc surface treated
Chromium1.580.645
Copper6.803.58
Cyanide1.040.430
Zinc5.232.19
Oil and grease71.643.0
TSS14769.8
pH( 1)( 1)

1 Within the range of 7.5 to 10.0 at all times.

(j) Alkaline cleaning spent baths.

Subpart H—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of zinc alkaline cleaned
Chromium0.0020.0007
Copper0.0070.004
Cyanide0.0010.0004
Zinc0.0050.002
Oil and grease0.0710.043
TSS0.1460.069
pH( 1) ( 1)

1 Within the range of 7.5 to 10.0 at all times.

(k) Alkaline cleaning rinse.

Subpart H—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of zinc alkaline cleaned
Chromium0.7440.304
Copper3.211.69
Cyanide0.4900.203
Zinc2.471.03
Oil and grease33.820.3
TSS69.333.0
pH( 1)( 1)

1 Within the range of 7.5 to 10.0 at all times.

(l) Sawing or grinding spent emulsions.

Subpart H—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of zinc sawed or ground with emulsions
Chromium0.0110.005
Copper0.0450.024
Cyanide0.0070.003
Zinc0.0350.015
Oil and grease0.4760.286
TSS0.9760.464
pH( 1) ( 1)

1 Within the range of 7.5 to 10.0 at all times.

(m) Electrocoating rinse.

Subpart H—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of zinc electrocoated
Chromium1.010.412
Copper4.352.29
Cyanide0.6640.275
Zinc3.351.40
Oil and grease45.827.5
TSS93.944.7
pH( 1)( 1)

1 Within the range of 7.5 to 10.0 at all times.

(n) Degreasing spent solvents—subpart H—BPT. There shall be no discharge of process wastewater pollutants.

[50 FR 34270, Aug. 23, 1985; 51 FR 2888, Jan. 22, 1986]
authority: Secs. 301, 304(b), (c), (e), and (g), 306(b) and (c), 307, 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) (the “Act”); 33 U.S.C. 1311,1314,c,e,and, 1316(b) andc,and; 86 Stat. 816, Pub. L. 92-500; 91 Stat. 1567, Pub. L. 95-217
source: 50 FR 34270, Aug. 23, 1985, unless otherwise noted.
cite as: 40 CFR 471.81