Regulations last checked for updates: May 18, 2024

Title 40 - Protection of Environment last revised: May 16, 2024
§ 471.31 - 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 125.30-125.32, any existing point source sub-

ject 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 C—BPT. There shall be no discharge of process wastewater pollutants.

(b) Rolling spent emulsions.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of nickel-cobalt rolled with emulsions
Chromium0.0750.031
Nickel0.3270.216
Fluoride10.14.49
Oil and grease3.42.04
TSS6.973.32
pH( 1)( 1)

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

(c) Rolling contact cooling water.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of nickel-cobalt rolled with water
Chromium1.660.679
Nickel7.244.79
Fluoride22599.6
Oil and grease75.445.3
TSS15573.5
pH( 1)( 1)

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

(d) Tube Reducing Spent Lubricant—subpart C—BPT. (1) There shall be no discharge of process wastewater pollutants except as provided under paragraph (d)(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 paragraph (d)(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 paragraph (d)(2) of this section, the actions described in paragraph (d)(4) of this section shall be taken, and the demonstration required under paragraph (d)(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 paragraph (d)(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 (d)(2) of this section; or

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

(iii) Determines the source of the pollutant whose concentration exceeded the level specified in paragraph (d)(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 (d)(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.

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

(f) Drawing spent emulsions.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of nickel-cobalt drawn with emulsions
Chromium0.0420.017
Nickel0.1830.121
Fluoride5.682.52
Oil and grease1.911.15
TSS3.911.86
pH( 1)( 1)

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

(g) Extrusion spent lubricants—subpart C—BPT. There shall be no discharge of process wastewater pollutants.

(h) Extrusion press or solution heat treatment contact cooling water.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of nickel-cobalt heat treated
Chromium0.0370.015
Nickel0.1600.106
Fluoride4.952.20
Oil and grease1.670.999
TSS3.411.63
pH( 1)( 1)

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

(i) Extrusion press hydraulic fluid leakage.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of nickel-cobalt extruded
Chromium0.1020.042
Nickel0.4460.295
Fluoride13.86.13
Oil and grease4.642.79
TSS9.514.53
pH( 1)( 1)

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

(j) Forging equipment cleaning wastewater.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of nickel-cobalt forged
Chromium0.0180.007
Nickel0.0770.051
Fluoride2.381.06
Oil and grease0.8000.480
TSS1.6400.780
pH( 1)( 1)

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

(k) Forging contact cooling water.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of forged nickel-cobalt cooled with water
Chromium0.2090.086
Nickel0.9100.602
Fluoride28.212.5
Oil and grease9.485.69
TSS19.59.25
pH( 1)( 1)

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

(l) Forging press hydraulic fluid leakage.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of nickel-cobalt forged
Chromium0.0830.034
Nickel0.3590.238
Fluoride11.24.94
Oil and grease3.742.25
TSS7.673.65
pH( 1)( 1)

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

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

(n) Stationary casting contact cooling water.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of nickel-cobalt cast with stationary casting methods
Chromium5.332.18
Nickel23.315.4
Fluoride720320
Oil and grease242145
TSS496236
pH( 1)( 1)

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

(o) Vacuum melting steam condensate—subpart C—BPT. There shall be no allowance for the discharge of process wastewater pollutants.

(p) Metal powder production atomization wastewater.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of nickel-cobalt metal powder atomized
Chromium1.160.472
Nickel5.033.33
Fluoride15669.2
Oil and grease52.431.5
TSS10851.1
pH( 1)( 1)

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

(q) Annealing and solution heat treatment contact cooling water—subpart C—BPT. There shall be no allowance for the discharge of process wastewater pollutants.

(r) Wet air pollution control scrubber blowdown.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of nickel-cobalt formed
Chromium0.3570.146
Nickel1.561.03
Fluoride48.221.4
Oil and grease16.29.72
TSS33.215.8
pH( 1)( 1)

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

(s) Surface treatment spent baths.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of nickel-cobalt surface treated
Chromium0.4120.169
Nickel1.801.19
Fluoride55.724.7
Oil and grease18.711.2
TSS38.418.3
pH( 1)( 1)

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

(t) Surface treatment rinse.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of nickel-cobalt surface treated
Chromium10.44.25
Nickel45.330.0
Fluoride1410623
Oil and grease472283
TSS968460
pH( 1)( 1)

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

(u) Alkaline cleaning spent baths.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of nickel-cobalt alkaline cleaned
Chromium0.0151.52
Nickel16.210.7
Fluoride502223
Oil and grease169101
TSS346165
pH( 1)( 1)

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

(v) Alkaline cleaning rinse.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of nickel-cobalt alkaline cleaned
Chromium1.030.420
Nickel4.482.96
Fluoride13961.5
Oil and grease46.628.0
TSS95.645.5
pH( 1)( 1)

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

(w) Molten salt rinse.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of nickel-cobalt treated with molten salt
Chromium3.721.52
Nickel16.210.7
Fluoride502223
Oil and grease169101
TSS346165
pH( 1)( 1)

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

(x) Ammonia rinse.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of nickel-cobalt treated with ammonia solution
Chromium0.0070.003
Nickel0.0290.019
Fluoride0.8810.391
Oil and grease0.2960.178
TSS0.6070.289
pH( 1)

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

(y) Sawing or grinding spent emulsions.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of nickel-cobalt sawed or ground with emulsions
Chromium0.0180.007
Nickel0.0760.050
Fluoride2.351.04
Oil and grease0.7880.473
TSS1.620.769
pH( 1)

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

(z) Sawing or grinding rinse.

Subpart C—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 nickel-cobalt rinsed
Chromium0.7970.326
Nickel3.482.30
Fluoride10847.8
Oil and grease36.221.7
TSS74.235.3
pH( 1)

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

(aa) Steam Cleaning Condensate.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of nickel-cobalt steam cleaned
Chromium0.0130.006
Nickel0.0580.039
Fluoride1.790.795
Oil and grease0.6020.361
TSS1.240.587
pH( 1)

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

(bb) Hydrostatic tube testing and ultrasonic testing wastewater—subpart C—BPT. There shall be no allowance for the discharge of process wastewater pollutants.

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

(dd) Dye penetrant testing wastewater.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of nickel-cobalt tested with dye penetrant method
Chromium0.0940.039
Nickel0.4090.271
Fluoride12.75.63
Oil and grease4.262.56
TSS8.744.16
pH( 1)( 1)

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

(ee) Electrocoating rinse.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of nickel-cobalt electrocoated
Chromium1.480.607
Nickel6.474.28
Fluoride20189.0
Oil and grease67.440.5
TSS13865.7
pH( 1)( 1)

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

(ff) Miscellaneous wastewater sources.

Subpart C—BPT

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/off-kg (pounds per million off-pounds) of nickel-cobalt formed
Chromium0.1080.044
Nickel0.4730.313
Fluoride14.76.50
Oil and grease4.922.95
TSS10.14.80
pH( 1)( 1)

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

[50 FR 34270, Aug. 23, 1985; 51 FR 2884, Jan. 22, 1986, as amended at 54 FR 11348, 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 471.31