40 CFR 471.22: Effluent limitations representing the degree of effluent reduction attainable by the application of the best available technology economically achievable (BAT).

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 representing the degree of effluent reduction attainable by the application of the best available technology economically achievable (BAT):

(a) Rolling spent emulsions.

Subpart B—BAT

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

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

Chromium 0.033 0.014

Zinc 0.109 0.046

Ammonia 9.95 4.37

Fluoride 4.44 1.97

(b) Forging spent lubricants—subpart B—BAT. There shall be no discharge of process wastewater pollutants.

(c) Forging contact cooling water.

Subpart B—BAT

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

mg/off-kg (pounds per million off-pounds) of forged magnesium cooled with water

Chromium 0.127 0.052

Zinc 0.422 0.177

Ammonia 38.5 17.0

Fluoride 17.2 7.63

(d) Forging equipment cleaning wastewater.

Subpart B—BAT

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

mg/off-kg (pounds per million off-pounds) of magnesium forged

Chromium 0.002 0.0007

Zinc 0.006 0.003

Ammonia 0.532 0.234

Fluoride 0.238 0.106

(e) Direct chill casting contact cooling water.

Subpart B—BAT

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

mg/off-kg (pounds per million off-pounds) of magnesium cast with direct chill methods

Chromium 1.74 0.711

Zinc 5.77 2.41

Ammonia 527 232

Fluoride 235 105

(f) Surface treatment spent baths.

Subpart B—BAT

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

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

Chromium 0.205 0.084

Zinc 0.681 0.285

Ammonia 62.1 27.3

Fluoride 27.8 12.3

(g) Surface treatment rinse.

Subpart B—BAT

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

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

Chromium 0.832 0.340

Zinc 2.76 1.16

Ammonia 252 111

Fluoride 113 49.9

(h) Sawing or grinding spent emulsions.

Subpart B—BAT

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

mg/off-kg (pounds per million off-pounds) of magnesium sawed or ground

Chromium 0.009 0.004

Zinc 0.029 0.012

Ammonia 2.60 1.15

Fluoride 1.16 0.515

(i) Degreasing spent solvents—subpart B—BAT. There shall be no discharge of process wastewater pollutants.

(j) Wet air pollution control scrubber blowdown.

Subpart B—BAT

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

mg/off-kg (pounds per million off-pounds) of magnesium sanded and repaired or forged

Chromium 0.273 0.112

Zinc 0.904 0.378

Ammonia 82.5 36.3

Fluoride 36.9 16.4