Section 420.03 - Alternative effluent limitations representing the degree of effluent reduction attainable by the application of best practicable control technology currently available, best available technology economically achievable, best available demonstrated control technology, and best conventional pollutant control technology (the "water bubble")(a) Except as provided in paragraphs (c) through (f) of this section, any existing or new direct discharging point source subject to this part may qualify for alternative effluent limitations to those specified in subparts A through M of this part, representing the degree of effluent reduction attainable by the application of best practicable control technology currently available (BPT), best available technology economically achievable (BAT), best conventional pollutant control technology (BCT), and best available demonstrated control technology (NSPS). The alternative effluent limitations for each pollutant are determined for a combination of outfalls by totaling the mass limitations allowed under subparts A through M of this part for each pollutant.(b) The water bubble may be used to calculate alternative effluent limitations only for identical pollutants (e.g., lead for lead, not lead for zinc).(d) A discharger cannot qualify for alternative effluent limitations if the application of such alternative effluent limitations would cause or contribute to an exceedance of any applicable water quality standards.(e) Each outfall from which process wastewaters are discharged must have specific, fixed effluent limitations for each pollutant limited by the applicable subparts A through M of this part.(f)Subcategory-specific restrictions:(1) There shall be no alternate effluent limitations for cokemaking process wastewater unless the alternative limitations are more stringent than the limitations in subpart A of this part.(2) There shall be no alternate effluent limitations for 2,3,7,8-TCDF in sintering process wastewater.(3) There shall be no alternate effluent limitations for O&G in sintering process wastewater unless the alternative limitations are more stringent than the otherwise applicable limitations in subpart B of this part.67 FR 64261, Oct. 17, 2002, as amended at 70 FR 73623, Dec. 13, 2005