Chromium monitoring parameter) 0.72 0.39 1.97 1.34 0.81 0.76 0.31 0.17 0.86 Chromium 0.41 monitoring parameter) 20.37 20.37 (48 FR 49149, Oct. 24, 1983; 49 FR 11631 and 11632, Mar. 27, 1984) Chromium 0.16 Cyanide 0.11 Zinc 0.53 Aluminum 2.34 Oil and grease 7.32 Suspended solids 15.0 PH .... (') Within the range of 7.0 to 10.0 at all times. 0.066 0.044 0.22 1.16 4.39 7.13 (') $ 467.31 Specialized definitions. For the purpose of this subpart: (a) The "core" of the extrusion subcategory shall include extrusion die cleaning, dummy block cooling, stationary casting, artificial aging, annealing, degreasing, and sawing. (b) The term "extrusion die cleaning" shall mean the process by which the steel dies used in extrusion of aluminum are cleaned. The term includes a dip into a concentrated caustic bath to dissolve the aluminum followed by a water rinse. It also includes the use of a wet scrubber with the die cleaning operation. (c) The term “ancillary operation” shall mean any operation not previously included in the core, performed on-site, following or preceding the extrusion operation. The ancillary operations shall include direct chill casting, press or solution heat treatment, cleaning or etching, degassing, and extrusion press hydraulic fluid leakage. $ 467.32 Effluent limitations rep resenting 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: 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 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. $ 467.33 Effluent limitations representing the degree of effluent reduction attainable by the application of the best available tech nology economically achievable. (a) 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: (b) There shall be no discharge allowance for wastewater pollutants from the degassing operation. (C) The discharge of wastewater pollutants from the core and ancillary operation except those in (b) of this section, shall not exceed the values set forth below: BAT effluent limitations Maximum for Maximum for any 1 day monthly aver age Core Pollutant or pollutant property Maximum for any 1 day Maximum for monthly aver age mg/off-kg (lb/million off-lbs) of Chromium Cyanide Zinc Aluminum aluminum extruded 0.90 0.59 2.98 13.10 0.37 0.25 1.25 6.52 Chromium 0.65 0.27 |
