CFR > Title 40 - Protection of Environment > CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY > SUBCHAPTER N—EFFLUENT GUIDELINES AND STANDARDS (Parts 400–471) > PART 471—NONFERROUS METALS FORMING AND METAL POWDERS POINT SOURCE CATEGORY > SUBPART B—Magnesium Forming Subcategory (§471.20 to §471.26) > 471.22—Effluent limitations representing the degree of effluent reduction attainable by the application of the best available technology economically achievable (BAT).

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
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