NR 256.04(1)(1) Total toxic organics. An indirect discharger may elect to monitor for oil and grease as an alternate to TTO under PSES and PSNS regulatory values. Due to the high solubility of toxic organics in oil and grease, compliance with the oil and grease standard is considered equivalent to compliance with the TTO standard.

NR 256.04(2)(2) Noncontinuous dischargers.

NR 256.04(2)(a)(a) For noncontinuous direct dischargers, the department shall apply effluent limitations or standards in the form of mass-based annual average, concentration-based maximum day and concentration-based maximum monthly average as indicated in the tables within this chapter.

NR 256.04(2)(b)(b) For noncontinuous indirect dischargers, the control authority may elect to establish concentration-based standards as outlined in sub. (3).

NR 256.04(3)(3) Conversion to concentration-based units.

NR 256.04(3)(a)(a) The control authority may apply concentration-based standards which are exactly equivalent to PSNS and PSES mass-based standards. Concentration-based standards shall be derived by the following procedure:

NR 256.04(3)(b)(b) Multiply PSNS or PSES mass-based standards by a) average production (kkg of metal poured), b) raw material usage (kkg of sand reclaimed), or c) air scrubber flow (Sm3 of air scrubbed), whichever applies, and divide by average discharge flow to the POTW. In calculating, use appropriate measurements and conversion factors to ensure that concentration-based units in mg/l result.

NR 256.04(4)(4) Monthly discharge limit. Compliance with the monthly discharge limits, as calculated from monthly average regulatory values from tables contained in this chapter, is required regardless of the number of samples analyzed and averaged.

NR 256.05(1)(1) Any existing source subject to this chapter which discharges to waters of the state shall achieve:

NR 256.05(2)(2) Any new source subject to this chapter which discharges to waters of the state shall achieve NSPS at the commencement of discharge.

NR 256.05(3)(3) Any existing source subject to this chapter which introduces process wastewater pollutants into a POTW shall achieve PSES by October 31, 1988.

NR 256.05(4)(4) Any new source subject to this chapter which introduces process wastewater pollutants into a POTW shall achieve PSNS at the commencement of discharge.

NR 256.10(1)(1) This subchapter applies to discharges to waters of the state and to introductions of pollutants into publicly owned treatment works from aluminum casting operations. It applies to a production process if the molten metal contains, on average, greater than 50% by weight of aluminum or if aluminum comprises the greatest percentage of the metal, measured by weight.

NR 256.10(2)(2) This subchapter does not apply to the casting of ingots, pigs or other cast shapes following primary metal smelting, which is regulated by the nonferrous metals manufacturing point source category under 40 CFR Part 421. This subchapter does not apply to the casting of aluminum performed as an integral part of aluminum forming and conducted on-site at an aluminum forming plant, which is regulated by the aluminum forming point source category under 40 CFR Part 467.

NR 256.10(3)(3) Processing operations following the cooling of castings, except for grinding scrubber operations, may be regulated by the aluminum forming point source category under 40 CFR Part 467, electroplating point source category under ch. NR 260, or metal finishing point source category under ch. NR 261.

NR 256.12NR 256.12 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 to 125.32, any existing point source subject to this subchapter, including noncontinuous direct dischargers, shall achieve the following BPT effluent limitations. Grinding scrubber operations may not discharge process wastewater pollutants to waters of the state.