{"data":{"id":"us/40-cfr-421.124","jurisdiction":"us","citation":"40 CFR 421.124","heading":"Standards of performance for new sources.","body":"Any new source subject to this subpart shall achieve the following new source performance standards:\n(a) Subpart L—Film Stripping.\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of silver from film stripping\nCopper 64.450 30.720\nZinc 51.360 21.150\nAmmonia (as N) 6,712.000 2,951.000\nTotal suspended solids 755.300 604.200\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(b) Subpart L—Film Stripping Wet Air Pollution Control and Precipitation and Filtration of Film Stripping Solutions Wet Air Pollution Control.\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of silver from precipitation and filtration of film stripping solutions\nCopper 1.242 .592\nZinc .990 .408\nAmmonia (as N) 129.300 56.840\nTotal suspended solids 14.550 11.640\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(c) Subpart L—Precipitation and Filtration of Film Stripping Solutions.\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of silver precipitated\nCopper 73.690 35.120\nZinc 58.720 24.180\nAmmonia (as N) 7,674.000 3,374.000\nTotal suspended solids 863.600 690.900\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(d) Subpart L—Precipitation and Filtration of Photographic Solutions.\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of silver precipitated\nCopper 34.048 16.226\nZinc 27.132 11.172\nAmmonia (as N) 3,545.000 1,559.000\nTotal suspended solids 399.000 319.200\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(e) Subpart L—Precipitation and Filtration of Photographic Solutions Wet Air Pollution Control.\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of silver from precipitation and filtration of photographic solutions\nCopper 15.540 7.406\nZinc 12.380 5.099\nAmmonia (as N) 1,618.000 711.400\nTotal suspended solids 182.100 145.700\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(f) Subpart L—Electrolytic Refining.\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of silver from electrolytic refining\nCopper .973 .464\nZinc .775 .319\nAmmonia (as N) 101.300 44.540\nTotal suspended solids 11.400 9.120\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(g) Subpart L—Furnace Wet Air Pollution Control.\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of silver roasted, smelted, or dried\nCopper .000 .000\nZinc .000 .000\nAmmonia (as N) .000 .000\nTotal suspended solids .000 .000\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(h) Subpart L—Leaching.\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of silver produced from leaching\nCopper .110 .053\nZinc .088 .036\nAmmonia (as N) 11.470 5.040\nTotal suspended solids 1.290 1.032\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(i) Subpart L—Leaching Wet Air Pollution Control and Precipitation of Nonphotographic Solutions Wet Air Pollution Control.\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of silver produced from leaching or silver precipitated\nCopper 5.671 2.703\nZinc 4.519 1.861\nAmmonia (as N) 590.500 259.600\nTotal suspended solids 66.450 53.160\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(j) Subpart L—Precipitation and Filtration of Nonphotograhic Solutions.\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of silver precipitated\nCopper 3.930 1.873\nZinc 3.132 1.290\nAmmonia (as N) 409.300 179.900\nTotal suspended solids 46.050 36.840\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(k) Subpart L—Floor and Equipment Washdown.\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of silver production\nCopper .000 .000\nZinc .000 .000\nAmmonia (as N) .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 L—Secondary Silver 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":"36c61d0b6386d1d12a68df633933c10403c526440f30f3617cf551cea17d5b6a","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-421.123","next":"us/40-cfr-421.125"},"notice":"GroundRules: Original legal text. Not legal advice."}