In addition to the definitions set forth in 40 CFR part 401, the following definitions apply to this part:

(a) Aluminum forming is a set of manufacturing operations in which aluminum and aluminum alloys are made into semifinished products by hot or cold working.

(b) Ancillary operation is a manufacturing operation that has a large flow, discharges significant amounts of pollutants, and may not be present at every plant in a subcategory, but when present is an integral part of the aluminum forming process.

(c) Contact cooling water is any wastewater which contacts the aluminum workpiece or the raw materials used in forming aluminum.

(d) Continuous casting is the production of sheet, rod, or other long shapes by solidifying the metal while it is being poured through an open-ended mold using little or no contact cooling water. Continuous casting of rod and sheet generates spent lubricants and rod casting also generates contact cooling water.

(e) Degassing is the removal of dissolved hydrogen from the molten aluminum prior to casting. Chemicals are added and gases are bubbled through the molten aluminum. Sometimes a wet scrubber is used to remove excess chlorine gas.

(f) Direct chill casting is the pouring of molten aluminum into a water-cooled mold. Contact cooling water is sprayed onto the aluminum as it is dropped into the mold, and the aluminum ingot falls into a water bath at the end of the casting process.

(g) Drawing is the process of pulling metal through a die or succession of dies to reduce the metal's diameter or alter its shape. There are two aluminum forming subcategories based on the drawing process. In the drawing with neat oils subcategory, the drawing process uses a pure or neat oil as a lubricant. In the drawing with emulsions or soaps subcategory, the drawing process uses an emulsion or soap solution as a lubricant.

(h) Emulsions are stable dispersions of two immiscible liquids. In the aluminum forming category this is usually an oil and water mixture.

(i) Cleaning or etching is a chemical solution bath and a rinse or series of rinses designed to produce a desired surface finish on the workpiece. This term includes air pollution control scrubbers which are sometimes used to control fumes from chemical solution baths. Conversion coating and anodizing when performed as an integral part of the aluminum forming operations are considered cleaning or etching operations. When conversion coating or anodizing are covered here they are not subject to regulation under the provisions of 40 CFR part 433, Metal Finishing.

(j) Extrusion is the application of pressure to a billet of aluminum, forcing the aluminum to flow through a die orifice. The extrusion subcategory is based on the extrusion process.

(k) Forging is the exertion of pressure on dies or rolls surrounding heated aluminum stock, forcing the stock to change shape and in the case where dies are used to take the shape of the die. The forging subcategory is based on the forging process.

(l) Heat treatment is the application of heat of specified temperature and duration to change the physical properties of the metal.

(m) Hot water seal is a heated water bath (heated to approximately 180 °F) used to seal the surface coating on formed aluminum which has been anodized and coated. In establishing an effluent allowance for this operation, the hot water seal shall be classified as a cleaning or etching rinse.

(n) In-process control technology is the conservation of chemicals and water throughout the production operations to reduce the amount of wastewater to be discharged.

(o) Neat oil is a pure oil with no or few impurities added. In aluminum forming its use is mostly as a lubricant.

(p) Rolling is the reduction in thickness or diameter of a workpiece by passing it between lubricated steel rollers. There are two subcategories based on the rolling process. In the rolling with neat oils subcategory, pure or neat oils are used as lubricants for the rolling process. In the rolling with emulsions subcategory, emulsions are used as lubricants for the rolling process.

(q) The term Total Toxic Organics (TTO) shall mean the sum of the masses or concentrations of each of the following toxic organic compounds which is found in the discharge at a concentration greater than 0.010 mg/1:

(r) Stationary casting is the pouring of molten aluminum into molds and allowing the metal to air cool.

(s) Wet scrubbers are air pollution control devices used to remove particulates and fumes from air by entraining the pollutants in a water spray.

(t) BPT means the best practicable control technology currently available under section 304(b)(1) of the Act.

(u) BAT means the best available technology economically achievable under section 304(b)(2)(B) of the Act.

(v) BCT means the best conventional pollutant control technology, under section 304(b)(4) of the Act.

(w) NSPS means new source performance standards under section 306 of the Act.

(x) PSES means pretreatment standards for existing sources, under section 307(b) of the Act.

(y) PSNS means pretreatment standards for new sources, under section 307(c) of the Act.

(z) The production normalizing mass (/kkg) for each core or ancillary operation is the mass (off-kkg or off-lb) processed through that operation.

(aa) The term off-kilogram (off-pound) shall mean the mass of aluminum or aluminum alloy removed from a forming or ancillary operation at the end of a process cycle for transfer to a different machine or process.

[48 FR 49149, Oct. 24, 1983; 49 FR 11631, Mar. 27, 1984, as amended at 53 FR 52369, Dec. 27, 1988]