(a) The provisions of this part are applicable to process wastewater discharges from all establishments or portions of establishments that manufacture the organic chemicals, plastics, and synthetic fibers (OCPSF) products or product groups covered by subparts B through H of this regulation and are included within the following U.S. Department of Commerce Bureau of the Census Standard Industrial Classification (SIC) major groups:

(g) Non-amenable cyanide. Discharges of cyanide in “cyanide-bearing waste streams” (listed in Appendix A to this part) are not subject to the cyanide limitations and standards of this part if the permit writer or control authority determines that the cyanide limitations and standards are not achievable due to elevated levels of non-amenable cyanide (i.e., cyanide that is not oxidized by chlorine treatment) that result from the unavoidable complexing of cyanide at the process source of the cyanide-bearing waste stream and establishes an alternative total cyanide or amenable cyanide limitation that reflects the best available technology economically achievable. The determination must be based upon a review of relevant engineering, production, and sampling and analysis information, including measurements of both total and amenable cyanide in the waste stream. An analysis of the extent of complexing in the waste stream, based on the foregoing information, and its impact on cyanide treatability shall be set forth in writing and, for direct dischargers, be contained in the fact sheet required by 40 CFR 124.8.

(h) Allowances for non-metal-bearing waste streams. Discharge limitations for chromium, copper, lead, nickel, and zinc or discharge standards for lead and zinc may be established for waste streams not listed in Appendix A of this part and not otherwise determined to be “metal-bearing waste streams” if the permit writer or control authority determines that the wastewater metals contamination is due to background levels that are not reasonably avoidable from sources such as intake water, corrosion of construction materials or contamination of raw materials. The determination must be based upon a review of relevant plant operating conditions, process chemistry, engineering, and sampling and analysis information. An analysis of the sources and levels of the metals, based on the foregoing information, shall be set forth in writing; for direct dischargers, the analysis shall be contained in the fact sheet required by 40 CFR 124.8. For direct dischargers, the permit writer may establish limitations for chromium, copper, lead, nickel, and zinc for non-“metal-bearing waste streams” between the lowest level which the permit writer determines based on best professional judgment can be reliably measured and the concentrations of such metals present in the wastestreams, but not to exceed the applicable limitations contained in §§ 414.91 and 414.101. (For zinc, the applicable limitations which may not be exceeded are those appearing in the tables in §§ 414.91 and 414.101, not the alternative limitations for rayon fiber manufacture by the viscose process and the acrylic fiber manufacture by the zinc chloride/solvent process set forth in footnote 2 to each of these tables.) For indirect dischargers, the control authority may establish standards for lead and zinc for non-“metal-bearing waste streams” between the lowest level which the control authority determines based on best professional judgment can be reliably measured and the concentration of such metals present in the wastestreams, but not to exceed the applicable standards contained in §§ 414.25, 414.35, 414.45, 414.55, 414.65, 414.75, and 414.85. (For zinc, the applicable standards which may not be exceeded are those appearing in the tables in the above referenced sections, not the alternative standards for rayon filber manufacture by the viscose process set forth in footnote 2 to the table in § 414.25, or the alternative standards for acrylic fiber manufacture by the zinc chloride/solvent process set forth in footnote 2 to the table in § 414.35.) The limitations and standards for individual dischargers shall be set on a mass basis by multiplying the concentration allowance established by the permit writer or control authority by the process wastewater flow from the individual wastestreams for which incidental metals have been found to be present.

(i) BOD5 and TSS limitations for plants with production in two or more subcategories. Any existing or new source direct discharge point source subject to two or more of subparts B through H must achieve BOD5 and TSS discharges not exceeding the quantity (mass) determined by multiplying the total OCPSF process wastewater flow subject to subparts B through H times the following “OCPSF production-proportioned concentration”: For a specific plant, let wj be the proportion of the plant's total OCPSF production in subcategory j. Then the plant-specific production-proportioned concentration limitations are given by: