40 CFR 437.31 - Effluent limitations attainable by the application of the best practicable control technology currently available (BPT).

Regulations last checked for updates: Dec 18, 2025

Title 40 - Protection of Environment last revised: Dec 11, 2025

View all text of Subpart C [§ 437.30 - § 437.36]

§ 437.31 - Effluent limitations attainable by the application of the best practicable control technology currently available (BPT).

Except as provided in 40 CFR 125.30 through 125.32 or § 437.30(b), any existing point source subject to this subpart must achieve the following effluent limitations representing the application of BPT:

BPT Limitations

Regulated parameter	Maximum daily ¹	Maximum monthly avg. ¹
Conventional Parameters
BOD5	163	53.0
pH	( ²)	( ²)
TSS	216	61.3
Metal Parameters
Copper	0.865	0.757
Zinc	0.497	0.420
Organic Parameters
Acetone	30.2	7.97
Acetophenone	0.114	0.0562
2-Butanone	4.81	1.85
o-Cresol	1.92	0.561
p-Cresol	0.698	0.205
Phenol	3.65	1.08
Pyridine	0.370	0.182
2,4,6-Trichlorophenol	0.155	0.106

¹ mg/L (ppm).

² Within the range 6 to 9.

[65 FR 81300, Dec. 22, 2000, as amended at 68 FR 71023, Dec. 22, 2003]

authority: 33 U.S.C. 1311,1314,1316,1317,1318,1342,and

source: 65 FR 81300, Dec. 22, 2000, unless otherwise noted.

cite as: 40 CFR 437.31