{"data":{"id":"us/40-cfr-421.112","jurisdiction":"us","citation":"40 CFR 421.112","heading":"Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available.","body":"Except as provided in 40 CFR 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable technology currently available:\n(a) Subpart K—Concentrate Digestion Wet Air Pollution Control.\nBPT Effluent Limitations\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pounds per million pounds) of concentrate digested\nLead 2.612 1.244\nZinc 9.080 3.794\nAmmonia (as N) 829.000 364.500\nFluoride 217.700 124.400\nTotal suspended solids 255.000 121.300\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(b) Subpart K—Solvent Extraction Raffinate.\nBPT Effluent Limitations\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pounds per million pounds) of concentrate digested\nLead 3.888 1.851\nZinc 13.520 5.647\nAmmonia (as N) 1,233.000 542.500\nFluoride 324.000 185.100\nTotal Suspended Solids 379.500 189.500\npH (1) (1)\nWithin the range of 7.5 to 10.0 at all times.\n(c) Subpart K—Solvent Extraction Wet Air Pollution Control.\nBPT Effluent Limitations\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pounds per million pounds) of concentrate digested\nLead 1.032 .491\nZinc 3.586 1.498\nAmmonia (as N) 327.400 143.900\nFluoride 85.960 49.120\nTotal suspended solids 100.700 47.890\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(d) Subpart K—Precipitation and Filtration.\nBPT Effluent Limitations\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pounds per million pounds) of concentrate digested\nLead 5.750 2.738\nZinc 19.990 8.350\nAmmonia (as N) 1,825.000 802.200\nFluoride 479.100 273.800\nTotal suspended solids 561.300 267.000\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(e) Subpart K—Precipitation and Filtration Wet Air Pollution Control.\nBPT Effluent Limitations\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pounds per million pounds) of concentrate digested\nLead 26.680 12.700\nZinc 92.730 38.740\nAmmonia (as N) 8,466.000 3,722.000\nFluoride 2,223.000 1,270.000\nTotal suspended solids 2,604.000 1,239.000\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(f) Subpart K—Tantalum Salt Drying.\nBPT Effluent Limitations\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pounds per million pounds) of tantalum salt dried\nLead 25.430 12.110\nZinc 88.390 36.930\nAmmonia (as N) 8,070.000 3,548.000\nFluoride 2,119.000 1,211.000\nTotal suspended solids 2,482.000 1,181.000\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(g) Subpart K—Oxides Calcining Wet Air Pollution Control.\nBPT Effluent Limitations\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pounds per million pounds) of columbium-tantalum oxide dried\nLead 16.140 7.685\nZinc 56.100 23.440\nAmmonia (as N) 5,122.000 2,252.000\nFluoride 1,345.000 768.500\nTotal suspended solids 1,576.000 749.200\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(h) Subpart K—Reduction of Tantalum Salt to Metal.\nBPT Effluent Limitations\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pounds per million pounds) of tantalum salt reduced\nLead 69.750 33.220\nZinc 242.500 101.300\nAmmonia (as N) 22,140.000 9,732.000\nFluoride 5,813.000 3,322.000\nTotal suspended solids 6,809.000 3,239.000\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(i) Subpart K—Reduction of Tantalum Salt to Metal Wet Air Pollution Control.\nBPT Effluent Limitations\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pounds per million pounds) of tantalum salt reduced\nLead .858 .409\nZinc 2.983 1.246\nAmmonia (as N) 272.400 119.700\nFluoride 71.510 40.860\nTotal suspended solids 83.770 39.840\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(j) Subpart K—Tantalum Powder Wash.\nBPT Effluent Limitations\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pounds per million pounds) of tantalum power washed\nLead 8.582 4.087\nZinc 29.830 12.470\nAmmonia (as N) 2,724.000 1,198.000\nFluoride 715.200 408.700\nTotal suspended solids 837.800 398.500\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(k) Subpart K—Consolidation and Casting Contact Cooling.\nBPT Effluent Limitations\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pounds per million pounds) of columbium or tantalum cast or consolidated\nLead .000 .000\nZinc .000 .000\nAmmonia (as N) .000 .000\nFluoride .000 .000\nTotal suspended solids .000 .000\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER N—EFFLUENT GUIDELINES AND STANDARDS","PART 421—NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY","Subpart K—Primary Columbium-Tantalum Subcategory"],"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":"0a9cd848da5b4e99d2314259bb071f6f242e78e8bfe7bace9db63629ecdd9496","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-421.111","next":"us/40-cfr-421.113"},"notice":"GroundRules: Original legal text. Not legal advice."}