40 CFR § 420.42 - Effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT).

---
identifier: "/us/cfr/t40/s420.42"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 420.42 - Effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT)."
title_number: 40
title_name: "Protection of Environment"
section_number: "420.42"
section_name: "Effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT)."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "N"
subchapter_name: "EFFLUENT GUIDELINES AND STANDARDS"
part_number: "420"
part_name: "IRON AND STEEL 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: "33 U.S.C. 1311, 1314, 1316, 1317, 1318, 1342, and 1361."
regulatory_source: "47 FR 23284, May 27, 1982, unless otherwise noted."
cfr_part: "420"
---


# 420.42 Effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT).

Except as provided in 40 CFR 125.30 through 125.32, any existing point source subject to this subpart must achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available.

(a) *Electric arc furnace steelmaking—semi-wet.* No discharge of process wastewater pollutants to navigable waters.

(b) *Basic oxygen furnace steelmaking—wet-suppressed combustion.*

Subpart D

|  |  |  |
| --- | --- | --- |
|  | Kg/kkg (pounds per 1,000 lb) of Product |  |
| TSS | 0.0312 | 0.0104 |
| pH | () | () |
| Within the range of 6.0 to 9.0 |  |  |

(c) *Basic oxygen furnace steelmaking—wet open combustion; and electric arc furnace steelmaking—wet.*

Subpart D

|  |  |  |
| --- | --- | --- |
|  | Kg/kkg (pounds per 1,000 lb) of product |  |
| TSS | 0.0687 | 0.0229 |
| pH | () | () |
| Within the range of 6.0 to 9.0. |  |  |

(d) *Basic oxygen furnace steelmaking—semi-wet.* (1) No discharge of process wastewater pollutants to navigable waters.

(2) If the permittee demonstrates to the satisfaction of the permitting authority that safety considerations prevent attainment of these limitations, the permitting authority may establish alternative limitations on a best professional judgment basis.

[47 FR 23284, May 27, 1982, as amended at 67 FR 64267, Oct. 17, 2002]