{"data":{"id":"us/40-cfr-421.123","jurisdiction":"us","citation":"40 CFR 421.123","heading":"Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best available technology economically achievable.","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 available technology economically achievable:\n(a) Subpart L—Film Stripping.\nBAT Effluent Limitations\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\n(b) Subpart L—Film Stripping Wet Air Pollution Control and Precipitation and Filtration of Film Stripping Solutions Wet Air Pollution Control.\nBAT Effluent Limitations\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\n(c) Subpart L—Precipitation and Filtration of Film Stripping Solutions.\nBAT Effluent Limitations\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\n(d) Subpart L—Precipitation and Filtration of Photographic Solutions.\nBAT Effluent Limitations\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\n(e) Subpart L—Precipitation and Filtration of Photographic Solutions Wet Air Pollution Control.\nBAT Effluent Limitations\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\n(f) Subpart L—Electrolytic Refining.\nBAT Effluent Limitations\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\n(g) Subpart L—Furnace Wet Air Pollution Control.\nBAT Effluent Limitations\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\n(h) Subpart L—Leaching.\nBAT Effluent Limitations\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\n(i) Subpart L—Leaching Wet Air Pollution Control and Precipitation of Nonphotographic Solutions Wet Air Pollution Control.\nBAT Effluent Limitations\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\n(j) Subpart L—Precipitation and Filtration of Nonphotographic Solutions.\nBAT Effluent Limitations\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\n(k) Subpart L—Floor and Equipment Washdown.\nBAT Effluent Limitations\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","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":"25e879642a2bfe1f12aa43a2c73ccbef8513c830495c399fdb63eea79ade144f","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-421.122","next":"us/40-cfr-421.124"},"notice":"GroundRules: Original legal text. Not legal advice."}