40 CFR § 421.312 - 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/s421.312"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 421.312 - 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: "421.312"
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: "2026-03-24"
last_updated: "2026-03-24"
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"
---


# 421.312 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) Tungsten detergent wash and rinse.

BPT Limitations for the Secondary Tungsten and Cobalt Subcategory

| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
|  | mg/kg (pounds per million pounds) of tungsten scrap washed |  |
| Copper | 0.371 | 0.195 |
| Nickel | 0.374 | 0.248 |
| Ammonia (as N) | 25.990 | 11.430 |
| Cobalt | 0.768 | 0.337 |
| Tungsten | 1.357 | 0.542 |
| Oil and grease | 3.900 | 2.340 |
| Total suspended solids | 7.995 | 3.803 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. |  |  |

(b) Tungsten leaching acid.

BPT Limitations for the Secondary Tungsten and Cobalt Subcategory

| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
|  | mg/kg (pounds per million pounds) of tungsten produced |  |
| Copper | 4.885 | 2.571 |
| Nickel | 4.937 | 3.265 |
| Ammonia (as N) | 342.700 | 150.700 |
| Cobalt | 10.130 | 4.448 |
| Tungsten | 17.890 | 7.147 |
| Oil and grease | 51.420 | 30.850 |
| Total suspended solids | 105.400 | 50.140 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. |  |  |

(c) Tungsten post-leaching wash and rinse.

BPT Limitations for the Secondary Tungsten and Cobalt Subcategory

| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
|  | mg/kg (pounds per million pounds) of tungsten produced |  |
| Copper | 9.772 | 5.143 |
| Nickel | 9.875 | 6.532 |
| Ammonia (as N) | 685.600 | 301.400 |
| Cobalt | 20.263 | 8.897 |
| Tungsten | 35.800 | 14.300 |
| Oil and grease | 102.900 | 61.720 |
| Total suspended solids | 210.900 | 100.300 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. |  |  |

(d) Synthetic scheelite filtrate.

BPT Limitations for the Secondary Tungsten and Cobalt Subcategory

| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
|  | mg/kg (pounds per million pounds) of synthetic scheelite produced |  |
| Copper | 31.660 | 16.660 |
| Nickel | 31.990 | 21.160 |
| Ammonia (as N) | 2,221.000 | 976.300 |
| Cobalt | 65.644 | 28.824 |
| Tungsten | 116.000 | 46.320 |
| Oil and grease | 333.200 | 200.000 |
| Total suspended solids | 683.100 | 324.900 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. |  |  |

(e) Tungsten carbide leaching wet air pollution control.

BPT Limitations for the Secondary Tungsten and Cobalt Subcategory

| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
|  | mg/kg (pounds per million pounds) of tungsten carbide scrap leached |  |
| Copper | 3.327 | 1.751 |
| Nickel | 3.362 | 2.224 |
| Ammonia (as N) | 233.400 | 102.600 |
| Cobalt | 6.899 | 3.029 |
| Tungsten | 12.190 | 4.868 |
| Oil and grease | 35.020 | 21.010 |
| Total suspended solids | 71.790 | 34.150 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. |  |  |

(f) Tungsten carbide wash water.

BPT Limitations for the Secondary Tungsten and Cobalt Subcategory

| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
|  | mg/kg (pounds per million pounds) of tungsten carbide produced |  |
| Copper | 15.830 | 8.333 |
| Nickel | 16.000 | 10.580 |
| Ammonia (as N) | 1,111.000 | 488.300 |
| Cobalt | 32.832 | 14.416 |
| Tungsten | 58.000 | 23.170 |
| Oil and grease | 166.700 | 100.000 |
| Total suspended solids | 341.700 | 162.500 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. |  |  |

(g) Cobalt sludge leaching wet air pollution control.

BPT Limitations for the Secondary Tungsten and Cobalt Subcategory

| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
|  | mg/kg (pounds per million pounds) of cobalt produced from cobalt sludge |  |
| Copper | 67.990 | 35.780 |
| Nickel | 68.700 | 45.440 |
| Ammonia (as N) | 4,770.000 | 2,097.000 |
| Cobalt | 140.977 | 61.901 |
| Tungsten | 249.000 | 99.470 |
| Oil and grease | 715.600 | 429.400 |
| Total suspended solids | 1,467.000 | 697.700 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. |  |  |

(h) Crystallization decant.

BPT Limitations for the Secondary Tungsten and Cobalt Subcategory

| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
|  | mg/kg (pounds per million pounds) of cobalt produced |  |
| Copper | 79.140 | 41.650 |
| Nickel | 79.970 | 52.900 |
| Ammonia (as N) | 5,552.000 | 2,441.000 |
| Cobalt | 164.101 | 72.055 |
| Tungsten | 289.900 | 115.800 |
| Oil and grease | 833.000 | 499.800 |
| Total suspended solids | 1,708.000 | 812.200 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. |  |  |

(i) Acid wash decant.

BPT Limitations for the Secondary Tungsten and Cobalt Subcategory

| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
|  | mg/kg (pounds per million pounds) of cobalt produced |  |
| Copper | 36.220 | 19.060 |
| Nickel | 36.600 | 24.210 |
| Ammonia (as N) | 2,541.000 | 1,117.000 |
| Cobalt | 75.104 | 32.977 |
| Tungsten | 132.700 | 52.990 |
| Oil and grease | 381.300 | 228.800 |
| Total suspended solids | 781.600 | 371.700 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. |  |  |

(j) Cobalt hydroxide filtrate.

BPT Limitations for the Secondary Tungsten and Cobalt Subcategory

| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
|  | mg/kg (pounds per million pounds) of cobalt produced |  |
| Copper | 107.600 | 56.650 |
| Nickel | 108.800 | 71.940 |
| Ammonia (as N) | 7,551.000 | 3,320.000 |
| Cobalt | 223.189 | 97.999 |
| Tungsten | 394.300 | 157.500 |
| Oil and grease | 1,133.000 | 679.800 |
| Total suspended solids | 2,323.000 | 1,105.000 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. |  |  |

(k) Cobalt hydroxide filter cake wash.

BPT Limitations for the Secondary Tungsten and Cobalt Subcategory

| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
|  | mg/kg (pounds per million pounds) of cobalt produced |  |
| Copper | 207.200 | 109.100 |
| Nickel | 209.400 | 138.500 |
| Ammonia (as N) | 14,530.000 | 6,389.000 |
| Cobalt | 429.598 | 188.631 |
| Tungsten | 758.900 | 303.100 |
| Oil and grease | 2,181.000 | 1,309.000 |
| Total suspended solids | 4,471.000 | 2,126.000 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. |  |  |

[50 FR 38386, Sept. 20, 1985, as amended at 55 FR 31713, 31714, Aug. 3, 1990]