40 CFR 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

Chromium 0.0006 0.0003

Copper 0.003 0.002

Cyanide 0.0004 0.0002

Zinc 0.002 0.0009

Oil and grease 0.028 0.017

TSS 0.057 0.027

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

Chromium 0.236 0.0097

Copper 1.02 0.536

Cyanide 0.156 0.065

Zinc 0.783 0.327

Oil and grease 10.7 6.43

TSS 22.0 10.5

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

Chromium 0.003 0.001

Copper 0.011 0.006

Cyanide 0.002 0.0007

Zinc 0.009 0.004

Oil and grease 0.116 0.070

TSS 0.238 0.113

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

Chromium 0.222 0.091

Copper 0.960 0.505

Cyanide 0.147 0.061

Zinc 0.738 0.308

Oil and grease 10.1 6.06

TSS 20.7 9.85

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

Chromium 0.336 0.138

Copper 1.45 0.763

Cyanide 0.221 0.092

Zinc 1.12 0.466

Oil and grease 15.3 9.16

TSS 31.3 14.9

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

Chromium 0.039 0.016

Copper 0.169 0.089

Cyanide 0.026 0.011

Zinc 0.130 0.054

Oil and grease 1.78 1.07

TSS 3.64 1.73

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

Chromium 1.58 0.645

Copper 6.80 3.58

Cyanide 1.04 0.430

Zinc 5.23 2.19

Oil and grease 71.6 43.0

TSS 147 69.8

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

Chromium 0.002 0.0007

Copper 0.007 0.004

Cyanide 0.001 0.0004

Zinc 0.005 0.002

Oil and grease 0.071 0.043

TSS 0.146 0.069

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

Chromium 0.744 0.304

Copper 3.21 1.69

Cyanide 0.490 0.203

Zinc 2.47 1.03

Oil and grease 33.8 20.3

TSS 69.3 33.0

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

Chromium 0.011 0.005

Copper 0.045 0.024

Cyanide 0.007 0.003

Zinc 0.035 0.015

Oil and grease 0.476 0.286

TSS 0.976 0.464

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

Chromium 1.01 0.412

Copper 4.35 2.29

Cyanide 0.664 0.275

Zinc 3.35 1.40

Oil and grease 45.8 27.5

TSS 93.9 44.7

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.