40 CFR 471.21 - Effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT).

View all text of Subpart B [§ 471.20 - § 471.26]

§ 471.21 - 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 for the process operations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT):

(a) Rolling spent emulsions.

Subpart B—BPT

Pollutant or pollutant property	Maximum for any 1 day	Maximum for monthly average		mg/off-kg (pounds per million off-pounds) of magnesium rolled with emulsions		Chromiun	0.033	0.014	Zinc	0.109	0.046	Ammonia	9.95	4.37	Fluoride	4.440	1.97	Oil and grease	1.49	0.895	TSS	3.06	1.46	pH		( 1)

1 Within the range of 7.5 to 10.0 at all times.

(b) Forging spent lubricants—subpart B—BPT. There shall be no discharge of process wastewater pollutants.

(c) Forging contact cooling water.

Subpart B—BPT

Pollutant or pollutant property	Maximum for any 1 day	Maximum for monthly average		mg/off-kg (pounds per million off-pounds) of forged magnesium cooled with water		Chromium	1.27	0.520	Zinc	4.22	1.77	Ammonia	385	170	Fluoride	172	76.3	Oil and grease	57.8	34.7	TSS	119	56.4	pH		( 1)

1 Within the range of 7.5 to 10.0 at all times.

(d) Forging equipment cleaning wastewater.

Subpart B—BPT

Pollutant or pollutant property	Maximum for any 1 day	Maximum for monthly average		mg/off-kg (pounds per million off-pounds) of magnesium forged		Chromium	0.018	0.007	Zinc	0.059	0.025	Ammonia	5.32	2.34	Fluoride	2.38	1.06	Oil and grease	0.798	0.479	TSS	1.64	0.778	pH		( 1)

1 Within the range of 7.5 to 10.0 at all times.

(e) Direct chill casting contact cooling water.

Subpart B—BPT

Pollutant or pollutant property	Maximum for any 1 day	Maximum for monthly average		mg/off-kg (pounds per million off-pounds) of magnesium cast with direct chill methods		Chromium	1.74	0.711	Zinc	5.77	2.41	Ammonia	527	232	Fluoride	235	105	Oil and grease	79.0	47.4	TSS	162	77.1	pH		( 1)

1 Within the range of 7.5 to 10.0 at all times.

(f) Surface treatment spent baths.

Subpart B—BPT

Pollutant or pollutant property	Maximum for any 1 day	Maximum for monthly average		mg/off-kg (pounds per million off-pounds) of magnesium surface treated		Chromium	0.205	0.084	Zinc	0.681	0.285	Ammonia	62.1	27.3	Fluoride	27.8	12.3	Oil and grease	9.32	5.59	TSS	19.1	9.09	pH		( 1)

1 Within the range of 7.5 to 10.0 at all times.

(g) Surface treatment rinse.

Subpart B—BPT

Pollutant or pollutant property	Maximum for any 1 day	Maximum for monthly average		mg/off-kg (pounds per million off-pounds) of magnesium surface treated		Chromium	8.32	3.4	Zinc	27.6	11.5	Ammonia	2520	1110	Fluoride	1130	499	Oil and grease	378	227	TSS	775	369	pH		( 1)

1 Within the range of 7.5 to 10.0 at all times.

(h) Sawing or grinding spent emulsions.

Subpart B—BPT

Pollutant or pollutant property	Maximum for any 1 day	Maximum for monthly average		mg/off-kg (pounds per million off-pounds) of magnesium sawed or ground		Chromium	0.009	0.004	Zinc	0.029	0.012	Ammonia	2.60	1.15	Fluoride	1.16	0.515	Oil and grease	0.390	0.234	TSS	0.800	0.381	pH		( 1)

1 Within the range of 7.5 to 10.0 at all times.

(i) Degreasing spent solvents—subpart B—BPT. There shall be no discharge of process wastewater pollutants.

(j) Wet air pollution control scrubber blowdown.

Subpart B—BPT

Pollutant or pollutant property	Maximum for any 1 day	Maximum for monthly average		mg/off-kg (pounds per million off-pounds) of magnesium sanded and repaired or forged		Chromium	0.273	0.112	Zinc	0.904	0.378	Ammonia	82.5	36.3	Fluoride	36.9	16.4	Oil and grease	12.4	7.43	TSS	25.4	12.1	pH		( 1)

1 Within the range of 7.5 to 10.0 at all times.