Effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available.

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 practicable control technology currently available: Subpart C Core Pollutant or pollutant property BPT effluent limitations Maximum for any 1 day Maximum for monthly average mg/off-kg (lb/million off-lbs) of aluminum extruded Chromium 0.16 0.066 Cyanide 0.11 0.044 Zinc 0.53 0.22 Aluminum 2.34 1.16 Oil and grease 7.32 4.39 Suspended solids 15.0 7.13 pH ( 1 ) ( 1 ) 1 Within the range of 7.0 to 10.0 at all times. Subpart C Extrusion Press Leakage Pollutant or pollutant property BPT effluent limitations Maximum for any 1 day Maximum for monthly average mg/off-kg (lb/million off-lbs) of aluminum extruded Chromium 0.65 0.27 Cyanide 0.43 0.18 Zinc 2.16 0.90 Aluminum 9.51 4.73 Oil and grease 29.56 17.74 Suspended solids 60.60 28.82 pH ( 1 ) ( 1 ) 1 With the range of 7.0 to 10.0 at all times. Subpart C Direct Chill Casting Contact Cooling Water Pollutant or pollutant property BPT effluent limitations Maximum for any 1 day Maximum for monthly average mg/off-kg (lb/million off-lbs) of aluminum cast Chromium 0.59 0.24 Cyanide 0.39 0.16 Zinc 1.94 0.81 Aluminum 8.55 4.26 Oil and grease 26.58 15.95 Suspended solids 54.49 25.92 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 C Press Heat Treatment Contact Cooling Water Pollutant or pollutant property BPT effluent limitations Maximum for any 1 day Maximum for monthly average mg/off-kg (lb/million off-lbs) of aluminum quenched Chromium 3.39 1.39 Cyanide 2.24 0.93 Zinc 11.25 4.70 Aluminum 49.55 24.66 Oil and grease 154.10 92.46 Suspended solids 315.91 150.25 pH ( 1 ) ( 1 ) 1 Within the range of 7.0 to 10.0 at all times. Subpart C Solution Heat Treatment Contact Cooling Water Pollutant or pollutant property BPT effluent limitations Maximum for any 1 day Maximum for monthly average mg/off-kg (lb/million off-lbs) of aluminum quenched Chromium 3.39 1.39 Cyanide 2.24 0.93 Zinc 11.25 4.70 Aluminum 49.55 24.66 Oil and grease 154.10 92.46 Suspended solids 315.91 150.25 pH ( 1 ) ( 1 ) 1 Within the range of 7.0 to 10.0 at all times. Subpart C Cleaning or Etching Bath Pollutant or pollutant property BPT effluent limitations Maximum for any 1 day Maximum for monthly average mg/off-kg (lb/million off-lbs) of aluminum cleaned or etched Chromium 0.079 0.032 Cyanide 0.052 0.022 Zinc 0.26 0.109 Aluminum 1.15 0.573 Oil and grease 3.58 2.15 Suspended solids 7.34 3.49 pH ( 1 ) ( 1 ) 1 Within the range of 7.0 to 10.0 at all times. Subpart C Cleaning or Etching Rinse Pollutant or pollutant property BPT effluent limitations Maximum for any 1 day Maximum for monthly average mg/off-kg (lb/million off-lbs) of aluminum cleaned or etched Chromium 6.12 2.51 Cyanide 4.04 1.67 Zinc 20.31 8.49 Aluminum 89.46 44.52 Oil and grease 278.24 166.95 Suspended solids 570.39 271.29 pH ( 1 ) ( 1 ) 1 Within the range of 7.0 to 10.0 at all times. Subpart C Cleaning or Etching Scrubber Liquor Pollutant or pollutant property BPT effluent limitations Maximum for any 1 day Maximum for monthly average mg/off-kg (lb/million off-lbs) of aluminum cleaned or etched Chromium 7.00 2.86 Cyanide 4.61 1.91 Zinc 23.22 9.70 Aluminum 102.24 50.88 Oil and grease 318.00 190.80 Suspended solids 651.90 310.05 pH ( 1 ) ( 1 ) 1 Within the range of 7.0 to 10.0 at all times. Subpart C Degassing Scrubber Liquor Pollutant or pollutant property BPT effluent limitations Maximum for any 1 day Maximum for monthly average mg/off-kg (lb/million off-lbs) of aluminum degassed Chromium 1.15 0.47 Cyanide 0.76 0.32 Zinc 3.81 1.59 Aluminum 16.78 8.35 Oil and grease 52.18 31.31 Suspended solids 106.97 50.88 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]