40 CFR § 421.232 - 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/s421.232"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 421.232 - 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: "421.232"
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"
---


# 421.232 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) Raw Material dust control.

BPT Limitations for the Primary Nickel and Cobalt Subcategory

| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
|  | mg/kg (pounds per million pounds) of copper, nickel, and cobalt in the crushed raw material |  |
| Copper | 0.146 | 0.077 |
| Nickel | 0.148 | 0.098 |
| Ammonia (as N) | 10.260 | 4.512 |
| Cobalt | 0.016 | 0.007 |
| Total suspended solids | 3.157 | 1.502 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. |  |  |

(b) Nickel wash water.

BPT Limitations for the Primary Nickel and Cobalt Subcategory

| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
|  | mg/kg (pounds per million pounds) of nickel powder washed |  |
| Copper | 0.064 | 0.034 |
| Nickel | 0.065 | 0.043 |
| Ammonia (as N) | 4.515 | 1.985 |
| Cobalt | 0.007 | 0.003 |
| Total suspended solids | 1.389 | 0.660 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. |  |  |

(c) Nickel reduction decant.

BPT Limitations for the Primary Nickel and Cobalt Subcategory

| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
|  | mg/kg (pounds per million pounds) of nickel produced |  |
| Copper | 24.120 | 12.700 |
| Nickel | 24.370 | 16.120 |
| Ammonia (as N) | 1,692.000 | 743.900 |
| Cobalt | 2.666 | 1.143 |
| Total suspended solids | 520.500 | 247.600 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. |  |  |

(d) Cobalt reduction decant.

BPT Limitations for the Primary Nickel 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 | 40.660 | 21.400 |
| Nickel | 41.080 | 27.180 |
| Ammonia (as N) | 2,852.000 | 1,254.000 |
| Cobalt | 4.494 | 1.926 |
| Total suspended solids | 877.300 | 417.300 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. |  |  |