{"data":{"id":"us/40-cfr-471.91","jurisdiction":"us","citation":"40 CFR 471.91","heading":"Effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT).","body":"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):\n(a) Rolling spent neat oils—subpart I—BPT. There shall be no discharge of process wastewater pollutants.\n(b) Drawing spent lubricants—subpart I—BPT. There shall be no discharge of process wastewater pollutants.\n(c) Extrusion spend emulsions—subpart I—BPT. There shall be no discharge of process wastewater pollutants.\n(d) Extrusion press hydraulic fluid leakage.\nSubpart I—BPT\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/off-kg (pounds per million off-pounds) of zirconium-hafnium extruded\nChromium 0.104 0.043\nCyanide 0.069 0.029\nNickel 0.455 0.301\nAmmonia 31.6 13.9\nFluoride 14.1 6.26\nOil and grease 4.74 2.85\nTSS 9.72 4.62\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(e) Swaging spent neat oils—subpart I—BPT. There shall be no discharge of process wastewater pollutants.\n(f) Heat treatment contact cooling water.\nSubpart I—BPT\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/off-kg (pounds per million off-pounds) of zirconium-hafnium heat treated\nChromium 0.151 0.062\nCyanide 0.100 0.041\nNickel 0.659 0.436\nAmmonia 45.7 20.1\nFluoride 20.4 9.06\nOil and grease 6.86 4.12\nTSS 14.1 6.69\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(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.\n(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.\n(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.\n(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:\n(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\n(ii) Substitutes a new tube reducing lubricant and thereafter complies with the requirements of paragraph (g)(3) of this section; or\n(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.\n(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:\n(i) Any dilution caused by the other wastewaters is taken into account in determining the appropriate (i.e., lower) allowable discharge concentration; and\n(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.\n(h) Surface treatment spent baths.\nSubpart I—BPT\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/off-kg (pounds per million off-pounds) of zirconium-hafnium surface treated\nChromium 0.150 0.61\nCyanide 0.099 0.041\nNickel 0.653 0.432\nAmmonia 45.3 20\nFluoride 20.3 8.98\nOil and grease 6.80 4.08\nTSS 14 6.63\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(i) Surface treatment rinse.\nSubpart I—BPT\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/off-kg (pounds per million off-pounds) of zirkonium-hafnium surface treated\nChromium 3.91 1.60\nCyanide 2.58 1.07\nNickel 17.1 11.3\nAmmonia 1,190 521\nFluoride 529 235\nOil and grease 178 107\nTSS 364 173\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(j) Alkaline cleaning spent baths.\nSubpart I—BPT\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/off-kg (pounds per million off-pounds) of zirconium-hafnium alkaline cleaned\nChromium 0.704 0.288\nCyanide 0.464 0.192\nNickel 3.07 2.03\nAmmonia 214 93.8\nFluoride 95.2 42.3\nOil and grease 32 19.2\nTSS 65.6 31.2\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(k) Alkaline cleaning rinse.\nSubpart I—BPT\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/off-kg (pounds per million off-pounds) of zirconium-hafnium alkaline cleaned\nChromium 13.8 5.65\nCyanide 9.11 3.77\nNickel 60.3 39.9\nAmmonia 4,190 1,840\nFluoride 1,870 829\nOil and grease 628 377\nTSS 1,290 613\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(l) Sawing or grinding spent emulsions.\nSubpart I—BPT\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/off-kg (pounds per million off-pounds) of zirconium-hafnium sawed or ground with emulsions\nChromium 0.124 0.051\nCyanide 0.082 0.034\nNickel 0.540 0.357\nAmmonia 37.5 16.5\nFluoride 16.7 7.42\nOil and grease 5.62 3.37\nTSS 11.5 5.48\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(m) Wet air pollution control scrubber blowdown—subpart I—BPT. There shall be no allowance for the discharge of process wastewater pollutants.\n(n) Degreasing spent solvents—subpart I—BPT. There shall be no discharge of process wastewater pollutants.\n(o) Degreasing rinse—subpart I—BPT. There shall be no discharge or process wastewater pollutants.\n(p) Molten salt rinse.\nSubpart I—BPT\nPollutant or pollutant property Maximum for any 1 day Maximum for monthy average\nmg/off-kg (pounds per million off pounds) of zirconium-hafnium treated with molten salt\nChromium 3.33 1.360\nCyanide 2.20 0.907\nNickel 14.5 9.60\nAmmonia 1,010 443\nFluoride 450 200\nOil and grease 151 90.7\nTSS 310 148\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(q) Sawing or grinding contact cooling water.\nSubpart I—BPT\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/off-kg (pounds per million off-pounds) of zirconium-hafnium sawed or ground with contact cooling water\nChromium 0.142 0.058\nCyanide 0.093 0.039\nNickel 0.617 0.408\nAmmonia 42.8 18.8\nFluoride 19.1 8.48\nOil and grease 6.42 3.85\nTSS 13.2 6.26\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(r) Sawing on grinding rinse.\nSubpart I—BPT\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/off-kg (pounds per million off-pounds) of sawed or ground zirconium hafnium rinsed\nChromium 0.792 0.324\nCyanide 0.522 0.216\nNickel 3.46 2.29\nAmmonia 240 106\nFluoride 107 47.5\nOil and grease 36 21.6\nTSS 73.8 35.1\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(s) Sawing or grinding spent neat oils—subpart I—BPT. There shall be no discharge of process wastewater pollutants.\n(t) Inspection and testing wastewater.\nSubpart I—BPT\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/off-kg (pounds per million off-pounds) of zirconium-hafnium tested\nChromium 0.007 0.003\nCyanide 0.005 0.002\nNickel 0.030 0.020\nAmmonia 2.06 0.903\nFluoride 0.917 0.407\nOil and grease 0.308 0.185\nTSS 0.632 0.301\npH (1) (1)\n1 Within the range of 7.05 to 10.0 at all times.","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER N—EFFLUENT GUIDELINES AND STANDARDS","PART 471—NONFERROUS METALS FORMING AND METAL POWDERS POINT SOURCE CATEGORY","Subpart I—Zirconium-Hafnium Forming Subcategory"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-40.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:04Z","sha256":"ebcb21d04b6d783501101e631e7ac9d18ec4b590504691d4163316d524be7df8","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-471.90","next":"us/40-cfr-471.92"},"notice":"GroundRules: Original legal text. Not legal advice."}