{"data":{"id":"us/40-cfr-437.42","jurisdiction":"us","citation":"40 CFR 437.42","heading":"Effluent limitations attainable by the application of the best practicable control technology currently available (BPT).","body":"(a) Except as provided in 40 CFR 125.30 through 125.32 or § 437.40(b), any existing facility subject to this subpart which combines treated or untreated wastes from subparts A, B, or C of this part may be subject to Multiple Wastestream Subcategory effluent limitations representing the application of BPT set forth in paragraphs (b), (c), (d), or (e) of this section if the discharger agrees to the following conditions in its NPDES permit:\n(1) The discharger will meet the applicable Multiple Wastestream Subcategory limitations set forth in (b), (c), (d) or (e);\n(2) The discharger will notify its NPDES permit writer at the time of renewal or modification of its permit, of its desire to be subject to the Multiple Waste Subcategory by submitting to the NPDES permit writer an initial certification statement as described in § 437.41(a);\n(3) The discharger will submit to its NPDES permitting authority a periodic certification statement as described in § 437.41(b) once a year; and\n(4) The discharger will maintain at the office of the facility and make available for inspection the on-site compliance paperwork as described in § 437.41(c).\n(b) Combined waste receipts from subparts A, B, and C of this part. (1) As provided in § 437.42(a), any existing point source subject to this paragraph must achieve the following effluent limitations representing the application of BPT:\nBPT Limitations\nRegulated parameter Maximum daily 1 Maximum monthly avg. 1\nConventional Parameters\nBOD5 163 53.0\nO\u0026G 127 38.0\npH (2) (2)\nTSS 74.1 30.6\nMetal Parameters\nAntimony 0.249 0.206\nArsenic 0.162 0.104\nCadmium 0.0172 0.0102\nChromium 0.746 0.323\nCobalt 0.192 0.124\nCopper 0.500 0.242\nLead 0.350 0.160\nMercury 0.00234 0.000739\nNickel 3.95 1.45\nSilver 0.120 0.0351\nTin 0.409 0.120\nTitanium 0.0947 0.0618\nVanadium 0.218 0.0662\nZinc 0.497 0.420\nOrganic Parameters\nAcetone 30.2 7.97\nAcetophenone 0.114 0.0562\nBis(2-ethylhexyl) phthalate 0.215 0.101\n2-Butanone 4.81 1.85\nButylbenzyl phthalate 0.188 0.0887\nCarbazole 0.598 0.276\no-Cresol 1.92 0.561\np-Cresol 0.698 0.205\nn-Decane 0.948 0.437\nFluoranthene 0.0537 0.0268\nn-Octadecane 0.589 0.302\nPhenol 3.65 1.08\nPyridine 0.370 0.182\n2,4,6-Trichlorophenol 0.155 0.106\n1 mg/L (ppm).\n2 OSC Within the range 6 to 9.\n(2) The following in-plant limitations apply to metal-bearing wastewater containing cyanide:\nIn-Plant Limitations\nRegulated parameter Maximum daily 1 Maximum monthly avg. 1\nCyanide 500 178\n1 mg/L (ppm).\n(c) Combined waste receipts from subparts A and B of this part. (1) As provided in § 437.42(a), any existing point source subject to this paragraph must achieve the following effluent limitations representing the application of BPT:\nBPT Limitations\nRegulated parameter Maximum daily 1 Maximum monthly avg. 1\nConventional Parameters\nO\u0026G 127 38.0\npH (2) (2)\nTSS 74.1 30.6\nMetal Parameters\nAntimony 0.249 0.206\nArsenic 0.162 0.104\nCadmium 0.0172 0.0102\nChromium 0.746 0.323\nCobalt 0.192 0.124\nCopper 0.500 0.242\nLead 0.350 0.160\nMercury 0.00234 0.000739\nNickel 3.95 1.45\nSilver 0.120 0.0351\nTin 0.409 0.120\nTitanium 0.0947 0.0618\nVanadium 0.218 0.0662\nZinc 2.87 0.641\nOrganic Parameters\nBis(2-ethylhexyl) phthalate 0.215 0.101\nButylbenzyl phthalate 0.188 0.0887\nCarbazole 0.598 0.276\nn-Decane 0.948 0.437\nFluoranthene 0.0537 0.0268\nn-Octadecane 0.589 0.302\n1 mg/L (ppm).\n2 Within the range 6 to 9.\n(2) The following in-plant limitations apply to metal-bearing wastewater containing cyanide:\nIn-Plant Limitations\nRegulated parameter Maximum daily 1 Maximum monthly avg. 1\nCyanide 500 178\n1 mg/L (ppm).\n(d) Combined waste receipts from subparts A and C of this part. (1) As provided in § 437.42(a), any existing point source subject to this paragraph must achieve the following effluent limitations representing the application of BPT:\nBPT Limitations\nRegulated parameter Maximum daily 1 Maximum monthly avg. 1\nConventional Parameters\nBOD 5 163 53.0\nO\u0026G 205 50.2\npH (2) (2)\nTSS 60.0 31.0\nMetal Parameters\nAntimony 0.249 0.206\nArsenic 0.162 0.104\nCadmium 0.474 0.0962\nChromium 15.5 3.07\nCobalt 0.192 0.124\nCopper 0.865 0.757\nLead 1.32 0.283\nMercury 0.00234 0.000739\nNickel 3.95 1.45\nSilver 0.120 0.0351\nTin 0.409 0.120\nTitanium 0.0947 0.0618\nVanadium 0.218 0.0662\nZinc 0.497 0.420\nOrganic Parameters\nAcetone 30.2 7.97\nAcetophenone 0.114 0.0562\n2-Butanone 4.81 1.85\no-Cresol 1.92 0.561\np-Cresol 0.698 0.205\nPhenol 3.65 1.08\nPyridine 0.370 0.182\n2,4,6-Trichlorophenol 0.155 0.106\n1 mg/L (ppm).\n2 Within the range 6 to 9.\n(2) The following in-plant limitations apply to metal-bearing wastewater containing cyanide:\nIn-Plant Limitations\nRegulated parameter Maximum daily 1 Maximum monthly avg. 1\nCyanide 500 178\n1 mg/L (ppm).\n(e) Combined waste receipts from subparts B and C of this part. As provided in § 437.42(a), any existing point source subject to this paragraph must achieve the following effluent limitations representing the application of BPT:\nBPT Limitations\nRegulated parameter Maximum daily 1 Maximum monthly avg. 1\nConventional Parameters\nBOD5 163 53.0\nO\u0026G 127 38.0\npH (2) (2)\nTSS 74.1 30.6\nMetal Parameters\nArsenic 2.95 1.33\nCadmium 0.0172 0.0102\nChromium 0.746 0.323\nCobalt 56.4 18.8\nCopper 0.500 0.242\nLead 0.350 0.160\nMercury 0.0172 0.00647\nTin 0.335 0.165\nZinc 0.497 0.420\nOrganic Parameters\nAcetone 30.2 7.97\nAcetophenone 0.114 0.0562\nBis(2-ethylhexyl) phthalate 0.215 0.101\n2-Butanone 4.81 1.85\nButylbenzyl phthalate 0.188 0.0887\nCarbazole 0.598 0.276\no-Cresol 1.92 0.561\np-Cresol 0.698 0.205\nn-Decane 0.948 0.437\nFluoranthene 0.0537 0.0268\nn-Octadecane 0.589 0.302\nPhenol 3.65 1.08\nPyridine 0.370 0.182\n2,4,6-Trichlorophenol 0.155 0.106\n1 mg/L (ppm).\n2 Within the range 6 to 9.","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER N—EFFLUENT GUIDELINES AND STANDARDS","PART 437—THE CENTRALIZED WASTE TREATMENT POINT SOURCE CATEGORY","Subpart D—Multiple Wastestreams"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-40.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:04Z","sha256":"37f3ae18f0a82e6fe1ec29c118b39da8d2718a3146028902cae3857f00362ec9","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-437.41","next":"us/40-cfr-437.43"},"notice":"GroundRules: Original legal text. Not legal advice."}