40 CFR § 421.292 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available.
---
identifier: "/us/cfr/t40/s421.292"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 421.292 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available."
title_number: 40
title_name: "Protection of Environment"
section_number: "421.292"
section_name: "Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "N"
subchapter_name: "EFFLUENT GUIDELINES AND STANDARDS"
part_number: "421"
part_name: "NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "Secs. 301, 304 (b), (c), (e), and (g), 306 (b) and (c), 307 (b) and (c), 308 and 501 of the Clean Water Act (the Federal Water Pollution Control Act Amendments of 1972, as amended by the Clean Water Act of 1977) and the Water Quality Act of 1987 (the “Act”); 33 U.S.C. 1311, 1314 (b), (c), (e), and (g), 1316 (b) and (c), 1317 (b) and (c), 1318 and 1361; 86 Stat. 816, Pub. L. 92-500; 91 Stat. 1567, Pub. L. 95-217; 101 Stat. 7, Pub. L. 100-4."
regulatory_source: "49 FR 8790, Mar. 8, 1984, unless otherwise noted."
cfr_part: "421"
---
# 421.292 Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available.
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:
(a) Tin smelter SO<sub>2</sub> scrubber.
BPT Limitations for the Secondary Tin Subcategory
| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of crude tapped tin metal produced | |
| Arsenic | 19.220 | 8.554 |
| Lead | 3.863 | 1.840 |
| Iron | 11.040 | 5.611 |
| Tin | 3.495 | 2.024 |
| Total suspended solids | 377.100 | 179.400 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |
(b) Dealuminizing rinse.
BPT Limitations for the Secondary Tin Subcategory
| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of dealuminized scrap produced | |
| Lead | 0.015 | 0.007 |
| Cyanide (total) | 0.010 | 0.004 |
| Fluoride | 1.225 | 0.700 |
| Tin | 0.013 | 0.008 |
| Total suspended solids | 1.435 | 0.683 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |
(c) Tin mud acid neutralization filtrate.
BPT Limitations for the Secondary Tin Subcategory
| Pollutant or pollutant property | Minimum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of neutralized, dewatered tin mud produced | |
| Lead | 2.120 | 1.009 |
| Cyanide (total) | 1.464 | 0.606 |
| Fluoride | 176.600 | 100.400 |
| Tin | 1.918 | 1.110 |
| Total suspended solids | 206.900 | 98.420 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |
(d) Tin hydroxide wash.
BPT Limitations for the Secondary Tin Subcategory
| Pollutant or pollutant property | Minimum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of tin hydroxide washed | |
| Lead | 5.020 | 2.391 |
| Cyanide (total) | 3.466 | 1.434 |
| Fluoride | 418.400 | 237.900 |
| Tin | 4.542 | 2.630 |
| Total suspended solids | 490.100 | 233.100 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |
(e) Spent electrowinning solution from new scrap.
BPT Limitations for the Secondary Tin Subcategory
| Pollutant or pollutant property | Minimum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of cathode tin produced | |
| Lead | 7.056 | 3.360 |
| Cyanide (total) | 4.872 | 2.016 |
| Fluoride | 588.000 | 334.300 |
| Tin | 6.384 | 3.696 |
| Total suspended solids | 688.800 | 327.600 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |
(f) Spent electrowinning solution from municipal solid waste.
BPT Limitations for the Secondary Tin Subcategory
| Pollutant or pollutant property | Minimum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of MSW scrap used as raw material | |
| Lead | 0.050 | 0.024 |
| Cyanide (total) | 0.035 | 0.014 |
| Fluoride | 4.165 | 2.368 |
| Tin | 0.045 | 0.026 |
| Total suspended solids | 4.879 | 2.321 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |
(g) Tin hydroxide supernatant from scrap.
BPT Limitations for the Secondary Tin Subcategory
| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of tin metal recovered from scrap | |
| Lead | 23.370 | 11.130 |
| Cyanide (total) | 16.140 | 6.677 |
| Fluoride | 1,947.000 | 1,107.000 |
| Tin | 21.140 | 12.240 |
| Total suspended solids | 2,281.000 | 1,085.000 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |
(h) Tin hydroxide supernatant from plating solutions and sludges.
BPT Limitations for the Secondary Tin Subcategory
| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of tin metal recovered from plating solutions and sludges | |
| Lead | 48.30 | 23.00 |
| Cyanide (total) | 33.35 | 13.80 |
| Fluoride | 4,025.00 | 2,289.00 |
| Tin | 43.70 | 25.30 |
| Total suspended solids | 4,715.00 | 2,243.00 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |
(i) Tin hydroxide filtrate.
BPT Limitations for the Secondary Tin Subcategory
| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of tin metal produced | |
| Lead | 10.520 | 5.009 |
| Cyanide (total) | 7.263 | 3.005 |
| Fluoride | 876.500 | 498.400 |
| Tin | 9.517 | 5.510 |
| Total suspended solids | 1,027.000 | 488.400 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |