40 CFR 471.25: Pretreatment standards for new sources (PSNS).

Except as provided in 40 CFR 403.7, any new source subject to this subpart which introduces pollutants into a publicly owned treatment works must comply with 40 CFR part 403 and achieve the following pretreatment standards for new sources (PSNS). The mass of wastewater pollutants in magnesium forming process wastewater introduced into a POTW shall not exceed the following values:

(a) Rolling spent emulsions.

Subpart B—PSNS

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 0.028 0.011

Zinc 0.076 0.032

Ammonia 9.95 4.37

Fluoride 4.44 1.97

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

(c) Forging contact cooling water.

Subpart B—PSNS

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 0.107 0.044

Zinc 0.295 0.122

Ammonia 38.5 17.0

Fluoride 17.2 7.63

(d) Forging equipment cleaning wastewater.

Subpart B—PSNS

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 0.0006

Zinc 0.004 0.002

Ammonia 0.532 0.234

Fluoride 0.238 0.106

(e) Direct chill casting contact cooling water.

Subpart B—PSNS

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 1.46 0.593

Zinc 4.03 1.66

Ammonia 527 232

Fluoride 235 105

(f) Surface treatment spent baths.

Subpart B—PSNS

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 0.173 0.070

Zinc 0.476 0.196

Ammonia 62.1 27.3

Fluoride 27.8 12.3

(g) Surface treatment rinse.

Subpart B—PSNS

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 0.700 0.284

Zinc 1.93 0.794

Ammonia 252 111

Fluoride 113 49.9

(h) Sawing or grinding spent emulsions.

Subpart B—PSNS

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 0.007 0.003

Zinc 0.020 0.008

Ammonia 2.60 1.15

Fluoride 1.16 0.515

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

(j) Wet air pollution control scrubber blowdown.

Subpart B—PSNS

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 0.229 0.093

Zinc 0.632 0.260

Ammonia 82.5 36.3

Fluoride 36.9 16.4