40 CFR 471.41: 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 D—BPT. There shall be no discharge of process wastewater pollutants.

(b) Rolling spent emulsions.

Subpart D—BPT

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

mg/off-kg (pounds per million off-pounds) of precious metals rolled with emulsions

Chromium 0.026 0.012

Copper 0.147 0.077

Cyanide 0.023 0.010

Silver 0.032 0.013

Oil and grease 1.54 0.925

TSS 3.16 1.51

pH (1) (1)

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

(c) Drawing spent neat oils—subpart D—BPT. There shall be no discharge of process wastewater pollutants.

(d) Drawing spent emulsions.

Subpart D—BPT

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

mg/off-kg (pounds per million off-pounds) of precious metals drawn with emulsions

Cadmium 0.016 0.007

Copper 0.091 0.048

Cyanide 0.014 0.006

Silver 0.020 0.008

Oil and grease 0.950 0.570

TSS 1.95 0.926

pH (1) (1)

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

(e) Drawing spent soap solutions.

Subpart D—BPT

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

mg/off-kg (pounds per million off-pounds) of precious metals drawn with soap solutions

Cadmium 0.001 0.0005

Copper 0.006 0.003

Cyanide 0.0009 0.0004

Silver 0.001 0.0006

Oil and grease 0.063 0.038

TSS 0.128 0.061

pH (1) (1)

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

(f) Metal powder production wet atomization wastewater.

Subpart D—BPT

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

mg/off-kg (pounds per million off-pounds) of precious metals powder wet atomized

Cadmium 2.27 1.00

Copper 12.7 6.70

Cyanide 1.94 0.802

Silver 2.70 1.14

Oil and grease 134 80.2

TSS 274 130

pH (1) (1)

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

(g) Heat treatment contact cooling water.

Subpart D—BPT

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

mg/off-kg (pounds per million off-pounds) of extruded precious metals heat treated

Cadmium 1.42 0.626

Copper 7.93 4.17

Cyanide 1.21 0.501

Silver 1.71 0.709

Oil and grease 83.4 50.1

TSS 171 81.3

pH (1) (1)

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

(h) Semi-continuous or continuous casting contact cooling water.

Subpart D—BPT

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

mg/off-kg (pounds per million off-pounds) of precious metals cast by the semi-continuous or continuous method

Cadmium 3.50 1.55

Copper 19.6 10.3

Cyanide 2.99 1.24

Silver 4.23 1.75

Oil and grease 206 124

TSS 423 209

pH (1) (1)

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

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

(j) Direct chill casting contact cooling water.

Subpart D—BPT

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

mg/off-kg (pounds per million off-pounds) of precious metals cast by the direct chill method

Cadmium 3.67 1.62

Copper 20.5 10.8

Cyanide 3.13 1.30

Silver 4.43 1.84

Oil and grease 216 130

TSS 443 211

pH (1) (1)

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

(k) Shot casting contact cooling water.

Subpart D—BPT

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

mg/off-kg (pounds per million off-pounds) of precious metals shot cast

Cadmium 1.25 0.551

Copper 6.98 3.67

Cyanide 1.07 0.441

Silver 1.51 0.624

Oil and grease 73.4 44.1

TSS 151 71.6

pH (1) (1)

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

(l) Wet air pollution control scrubber blowdown—subpart D—BPT. There shall be no discharge of process wastewater pollutants.

(m) Pressure bonding contact cooling water.

Subpart D—BPT

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

mg/off-kg (pounds per million off-pounds) of precious metals and base metal pressure bonded

Cadmium 0.029 0.013

Copper 0.159 0.084

Cyanide 0.024 0.010

Silver 0.034 0.014

Oil and grease 1.67 1.00

TSS 3.43 1.63

pH (1) (1)

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

(n) Surface treatment spent baths.

Subpart D—BPT

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

mg/off-kg (pounds per million off-pounds) of precious metals surface treated

Cadmium 0.033 0.015

Copper 0.183 0.097

Cyanide 0.028 0.012

Silver 0.040 0.017

Oil and grease 1.93 1.16

TSS 3.95 1.88

pH (1) (1)

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

(o) Surface treatment rinse.

Subpart D—BPT

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

mg/off-kg (pounds per million off-pounds) of precious metals surface treated

Cadmium 2.10 0.924

Copper 11.7 5.16

Cyanide 1.79 0.739

Silver 2.53 1.05

Oil and grease 123 73.9

TSS 253 120

pH (1) (1)

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

(p) Alkaline cleaning spent baths.

Subpart D—BPT

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

mg/off-kg (pounds per million off-pounds) of precious metals alkaline cleaned

Cadmium 0.021 0.009

Copper 0.114 0.060

Cyanide 0.018 0.007

Silver 0.025 0.010

Oil and grease 1.20 0.720

TSS 2.46 1.170

pH (1) (1)

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

(q) Alkaline cleaning rinse.

Subpart D—BPT

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

mg/off-kg (pounds per million off-pounds) of precious metals alkaline cleaned

Cadmium 3.81 1.68

Copper 21.3 11.2

Cyanide 3.25 1.35

Silver 4.59 1.91

Oil and grease 224 135

TSS 459 219

pH (1) (1)

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

(r) Alkaline cleaning prebonding wastewater.

Subpart D—BPT

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

mg/off-kg (pounds per million off-pounds) of precious metals and base metal cleaned prior to bonding

Cadmium 3.95 1.74

Copper 22.1 11.6

Cyanide 3.37 1.39

Silver 4.76 1.97

Oil and grease 232 139

TSS 476 226

pH (1) (1)

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

(s) Tumbling or burnishing wastewater.

Subpart D—BPT

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

mg/off-kg (pounds per million off-pounds) of precious metals tumbled or burnished

Cadmium 4.12 1.82

Copper 23.0 12.1

Cyanide 3.51 1.45

Silver 4.96 2.06

Oil and grease 242 145

TSS 496 236

pH (1) (1)

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

(t) Sawing or grinding spent neat oils—subpart D—BPT. There shall be no discharge of process wastewater pollutants.

(u) Sawing or grinding spent emulsions.

Subpart D—BPT

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

mg/off-kg (pounds per million off-pounds) of precious metals sawed or ground with emulsions

Cadmium 0.032 0.014

Copper 0.178 0.094

Cyanide 0.027 0.011

Silver 0.039 0.016

Oil and grease 1.87 1.12

TSS 3.83 1.82

pH (1) (1)

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

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