Section 412.31 - Effluent limitations attainable by the application of the best practicable control technology currently available (BPT)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 application of BPT:
(a)For CAFO production areas. Except as provided in paragraphs (a)(1) through (a)(2) of this section, there must be no discharge of manure, litter, or process wastewater pollutants into waters of the U.S. from the production area. (1) Whenever precipitation causes an overflow of manure, litter, or process wastewater, pollutants in the overflow may be discharged into U.S. waters provided:(i) The production area is designed, constructed, operated and maintained to contain all manure, litter, and process wastewater including the runoff and the direct precipitation from a 25-year, 24-hour rainfall event;(ii) The production area is operated in accordance with the additional measures and records required by § 412.37(a) and (b) .(2)Voluntary alternative performance standards. Any CAFO subject to this subpart may request the Director to establish NPDES permit effluent limitations based upon site-specific alternative technologies that achieve a quantity of pollutants discharged from the production area equal to or less than the quantity of pollutants that would be discharged under the baseline performance standards as provided by paragraph (a)(1) of this section.(i)Supporting information. In requesting site-specific effluent limitations to be included in the NPDES permit, the CAFO owner or operator must submit a supporting technical analysis and any other relevant information and data that would support such site-specific effluent limitations within the time frame provided by the Director. The supporting technical analysis must include calculation of the quantity of pollutants discharged, on a mass basis where appropriate, based on a site-specific analysis of a system designed, constructed, operated, and maintained to contain all manure, litter, and process wastewater, including the runoff from a 25-year, 24-hour rainfall event. The technical analysis of the discharge of pollutants must include: (A) All daily inputs to the storage system, including manure, litter, all process waste waters, direct precipitation, and runoff.(B) All daily outputs from the storage system, including losses due to evaporation, sludge removal, and the removal of waste water for use on cropland at the CAFO or transport off site.(C) A calculation determining the predicted median annual overflow volume based on a 25-year period of actual rainfall data applicable to the site.(D) Site-specific pollutant data, including N, P, BOD5, TSS, for the CAFO from representative sampling and analysis of all sources of input to the storage system, or other appropriate pollutant data.(E) Predicted annual average discharge of pollutants, expressed where appropriate as a mass discharge on a daily basis (lbs/day), and calculated considering paragraphs (a)(2)(i)(A) through (a)(2)(i)(D) of this section.(ii) The Director has the discretion to request additional information to supplement the supporting technical analysis, including inspection of the CAFO.(3) The CAFO shall attain the limitations and requirements of this paragraph as of the date of permit coverage.(b)For CAFO land application areas. Discharges from land application areas are subject to the following requirements:(1) Develop and implement the best management practices specified in § 412.4 ;(2) Maintain the records specified at § 412.37 (c) ;(3) The CAFO shall attain the limitations and requirements of this paragraph by February 27, 2009.68 FR 7269, Feb. 12, 2003, as amended at 71 FR 6984, Feb. 10, 2006; 72 FR 40250, July 24, 2007