Regulations last checked for updates: May 18, 2024

Title 40 - Protection of Environment last revised: May 16, 2024
§ 471.91 - 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 neat oils—subpart I—BPT. There shall be no discharge of process wastewater pollutants.

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

(c) Extrusion spend emulsions—subpart I—BPT. There shall be no discharge of process wastewater pollutants.

(d) Extrusion press hydraulic fluid leakage.

Subpart I—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of zirconium-hafnium extruded
Chromium0.1040.043
Cyanide0.0690.029
Nickel0.4550.301
Ammonia31.613.9
Fluoride14.16.26
Oil and grease4.742.85
TSS9.724.62
pH( 1)( 1)

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

(e) Swaging spent neat oils—subpart I—BPT. There shall be no discharge of process wastewater pollutants.

(f) Heat treatment contact cooling water.

Subpart I—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of zirconium-hafnium heat treated
Chromium0.1510.062
Cyanide0.1000.041
Nickel0.6590.436
Ammonia45.720.1
Fluoride20.49.06
Oil and grease6.864.12
TSS14.16.69
pH( 1)( 1)

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

(g) Tube Reducing Spent Lubricant—subpart I—BPT. (1) There shall be no discharge of process wastewater pollutants except as provided under paragraph (g)(2) of this section.

(2) Process wastewater pollutants may be discharged, with no allowance for any pollutants discharged, provided the facility owner or operator demonstrates, on the basis of analytical methods set forth in or approved pursuant to 40 CFR part 136, that the concentrations of nitrosamine compounds in the wastewater discharged from the tube reducing process do not exceed 0.050 mg/l of N-nitrosodimethylamine, 0.020 mg/l of N-nitrosodiphenylamine, and 0.020 mg/l of N-nitrosodi-n-propylamine.

(3) The demonstration required under subparagraph (g)(2) of this section shall be made once per month until the demonstration has been made for all three nitrosamine compounds for six consecutive months, after which time the demonstration may be made once per quarter. If a sample is found to contain any of the foregoing nitrosamine compounds at concentrations greater than those specified in subparagraph (g)(2) of this section, the actions described in paragraph (g)(4), of this section shall be taken, and the demonstration required under paragraph (g)(2) of this section shall be made once per month until it has been made for all three nitrosamine compounds for six consecutive months.

(4) If sampling results show that any of the foregoing nitrosamine compounds is present in the process wastewater at concentrations greater than those specified in subparagraph (g)(2) of this section, the facility owner or operator shall ensure that, within thirty days of receiving written notification of the sampling results, there is no further discharge of tube reducing spent lubricant wastewater until the owner or operator:

(i) Performs a subsequent analysis which demonstrates that the concentrations of the foregoing nitrosamine compounds do not exceed the levels specified in paragraph (g)(2) of this section; or

(ii) Substitutes a new tube reducing lubricant and thereafter complies with the requirements of paragraph (g)(3) of this section; or

(iii) Determines the source of the pollutant whose concentration exceeded the level specified in paragraph (g)(2) of this section and demonstrates to the satisfaction of the NPDES issuing authority that such source has been eliminated.

(5) The concentration limits specified in paragraph (g)(2) of this section apply at the point of discharge from the tube reducing process. However, sampling after the tube reducing wastewater has been commingled with other wastewaters is permitted if:

(i) Any dilution caused by the other wastewaters is taken into account in determining the appropriate (i.e., lower) allowable discharge concentration; and

(ii) An analytical method of sufficient sensitivity is used to measure the levels of each of the foregoing nitrosamine compounds in the wastewaters being sampled.

(h) Surface treatment spent baths.

Subpart I—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of zirconium-hafnium surface treated
Chromium0.1500.61
Cyanide0.0990.041
Nickel0.6530.432
Ammonia45.320
Fluoride20.38.98
Oil and grease6.804.08
TSS146.63
pH( 1)( 1)

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

(i) Surface treatment rinse.

Subpart I—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of zirkonium-hafnium surface treated
Chromium3.911.60
Cyanide2.581.07
Nickel17.111.3
Ammonia1,190521
Fluoride529235
Oil and grease178107
TSS364173
pH( 1)( 1)

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

(j) Alkaline cleaning spent baths.

Subpart I—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of zirconium-hafnium alkaline cleaned
Chromium0.7040.288
Cyanide0.4640.192
Nickel3.072.03
Ammonia21493.8
Fluoride95.242.3
Oil and grease3219.2
TSS65.631.2
pH( 1)( 1)

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

(k) Alkaline cleaning rinse.

Subpart I—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of zirconium-hafnium alkaline cleaned
Chromium13.85.65
Cyanide9.113.77
Nickel60.339.9
Ammonia4,1901,840
Fluoride1,870829
Oil and grease628377
TSS1,290613
pH( 1)( 1)

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

(l) Sawing or grinding spent emulsions.

Subpart I—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of zirconium-hafnium sawed or ground with emulsions
Chromium0.1240.051
Cyanide0.0820.034
Nickel0.5400.357
Ammonia37.516.5
Fluoride16.77.42
Oil and grease5.623.37
TSS11.55.48
pH( 1)( 1)

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

(m) Wet air pollution control scrubber blowdown—subpart I—BPT. There shall be no allowance for the discharge of process wastewater pollutants.

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

(o) Degreasing rinse—subpart I—BPT. There shall be no discharge or process wastewater pollutants.

(p) Molten salt rinse.

Subpart I—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthy average
mg/off-kg (pounds per million off pounds) of zirconium-hafnium treated with molten salt
Chromium3.331.360
Cyanide2.200.907
Nickel14.59.60
Ammonia1,010443
Fluoride450200
Oil and grease15190.7
TSS310148
pH( 1)( 1)

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

(q) Sawing or grinding contact cooling water.

Subpart I—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of zirconium-hafnium sawed or ground with contact cooling water
Chromium0.1420.058
Cyanide0.0930.039
Nickel0.6170.408
Ammonia42.818.8
Fluoride19.18.48
Oil and grease6.423.85
TSS13.26.26
pH( 1)( 1)

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

(r) Sawing on grinding rinse.

Subpart I—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of sawed or ground zirconium hafnium rinsed
Chromium0.7920.324
Cyanide0.5220.216
Nickel3.462.29
Ammonia240106
Fluoride10747.5
Oil and grease3621.6
TSS73.835.1
pH( 1)( 1)

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

(s) Sawing or grinding spent neat oils—subpart I—BPT. There shall be no discharge of process wastewater pollutants.

(t) Inspection and testing wastewater.

Subpart I—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of zirconium-hafnium tested
Chromium0.0070.003
Cyanide0.0050.002
Nickel0.0300.020
Ammonia2.060.903
Fluoride0.9170.407
Oil and grease0.3080.185
TSS0.6320.301
pH( 1)( 1)

1 Within the range of 7.05 to 10.0 at all times.

[50 FR 34270, Aug. 23, 1985; 51 FR 2888, Jan. 22, 1986, as amended at 54 FR 11350, Mar. 17, 1989]
authority: Secs. 301, 304(b), (c), (e), and (g), 306(b) and (c), 307, 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) (the “Act”); 33 U.S.C. 1311,1314,c,e,and, 1316(b) andc,and; 86 Stat. 816, Pub. L. 92-500; 91 Stat. 1567, Pub. L. 95-217
source: 50 FR 34270, Aug. 23, 1985, unless otherwise noted.
cite as: 40 CFR 471.91