40 C.F.R. § 467.24
New source performance standards.
Cite as 40 C.F.R. § 467.24 (2026)
Any new source subject to this subpart must achieve the following performance standards. The discharge of process wastewater pollutants from the core shall not exceed the values set forth below: Subpart B Core Pollutant or pollutant property NSPS Maximum for any 1 day Maximum for monthly average mg/off-kg (lb/million off-lbs) of aluminum rolled with emulsions Chromium 0.048 0.020 Cyanide 0.026 0.011 Zinc 0.133 0.055 Aluminum 0.80 0.35 Oil and grease 1.30 1.30 Suspended solids 1.95 1.56 pH ( 1 ) ( 1 ) 1 Within the range of 7.0 to 10.0 at all times. Subpart B Direct Chill Casting Contact Cooling Water Pollutant or pollutant property NSPS Maximum for any 1 day Maximum for monthly average mg/off-kg (lb/million off-lbs) of aluminum cast by semicontinuous methods Chromium 0.49 0.20 Cyanide 0.27 0.11 Zinc 1.36 0.56 Aluminum 8.12 3.60 Oil and grease 13.29 13.29 Suspended solids 19.94 15.95 pH ( 1 ) ( 1 ) 1 The pH shall be maintained within the range of 7.0 to 10.0 at all times except for those situations when this waste stream is discharged separately and without commingling with any other wastewater in which case the pH shall be within the range of 6.0 to 10.0 at all times. Subpart B Solution Heat Treatment Contact Cooling Water Pollutant or pollutant property NSPS Maximum for any 1 day Maximum for monthly average mg/off-kg (lb/million off-lbs) of aluminum quenched Chromium 0.76 0.31 Cyanide 0.41 0.17 Zinc 2.08 0.86 Aluminum 12.45 5.52 Oil and grease 20.37 20.37 Suspended solids 30.56 24.45 pH ( 1 ) ( 1 ) 1 Within the range of 7.0 to 10.0 at all times. Subpart B Cleaning or Etching Bath Pollutant or pollutant property NSPS Maximum for any 1 day Maximum for monthly average mg/off-kg (lb/million off-lbs) of aluminum cleaned or etched Chromium 0.067 0.027 Cyanide 0.036 0.015 Zinc 0.183 0.075 Aluminum 1.094 0.485 Oil and grease 1.79 1.79 Suspended solids 2.69 2.15 pH ( 1 ) ( 1 ) 1 Within the range of 7.0 to 10.0 at all times. Subpart B Cleaning or Etching Rinse Pollutant or pollutant property NSPS Maximum for any 1 day Maximum for monthly average mg/off-kg (lb/million off-lbs) of aluminum cleaned or etched Chromium 0.52 0.21 Cyanide 0.28 0.11 Zinc 1.42 0.59 Aluminum 8.50 3.77 Oil and grease 13.91 13.91 Suspended solids 20.87 16.70 pH ( 1 ) ( 1 ) 1 Within the range of 7.0 to 10.0 at all times. Subpart B Cleaning or Etching Scrubber Liquor Pollutant or pollutant property NSPS Maximum for any 1 day Maximum for monthly average mg/off-kg (lb/million off-lbs) of aluminum cleaned or etched Chromium 0.72 0.29 Cyanide 0.39 0.16 Zinc 1.97 0.81 Aluminum 11.81 5.24 Oil and grease 19.33 19.33 Suspended solids 29.00 23.20 pH ( 1 ) ( 1 ) 1 Within the range of 7.0 to 10.0 at all times. [48 FR 49149, Oct. 24, 1983; 49 FR 11631, 11633, Mar. 27, 1984, as amended at 53 FR 52370, Dec. 27, 1988]