Regulations last checked for updates: Nov 23, 2024
Title 40 - Protection of Environment last revised: Nov 21, 2024
§ 421.250 - Applicability: Description of the primary precious metals and mercury subcategory.
The provisions of this subpart are applicable to discharges resulting from the production of gold, silver, or mercury by primary precious metals and mercury facilities.
§ 421.251 - Specialized definitions.
For the purpose of this subpart the general definitions, abbreviations, and methods of analysis set forth in 40 CFR part 401 shall apply to this subpart.
§ 421.252 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available.
Except as provided in 40 CFR 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable technology currently available:
(a) Smelter wet air pollution control.
BPT Limitations for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/troy ounce of gold and silver smelted
|
| Lead | 0.546 | 0.260
|
| Mercury | 0.325 | 0.130
|
| Silver | 0.533 | 0.221
|
| Zinc | 1.898 | 0.793
|
| Gold | 0.130 | |
| Oil and grease | 26.000 | 15.600
|
| Total suspended solids | 53.300 | 25.350
|
| pH | (
1) | (
1)
|
(b) Silver chloride reduction spent solution.
BPT Limitations for the Primary Precious Metals and Mercury Subcategory
| Pollutant of pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/troy ounce of silver reduced in solution
|
| Lead | 0.168 | 0.080
|
| Mercury | 0.100 | 0.040
|
| Silver | 0.164 | 0.068
|
| Zinc | 0.584 | 0.244
|
| Gold | 0.040 | |
| Oil and grease | 8.000 | 4.800
|
| Total suspended solids | 16.400 | 7.800
|
| pH | (
1) | (
1)
|
(c) Electrolytic cells wet air pollution control.
BPT Limitations for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/troy ounce of gold refined electrolytically
|
| Lead | 83.160 | 39.600
|
| Mercury | 49.500 | 19.800
|
| Silver | 81.180 | 33.660
|
| Zinc | 289.100 | 120.800
|
| Gold | 19.800 | |
| Oil and grease | 3,960.000 | 2,376.000
|
| Total suspended solids | 8,118.000 | 3,861.000
|
| pH | (
1) | (
1)
|
(d) Electrolyte preparation wet air pollution control.
BPT Limitations for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/troy ounce of silver in electrolyte produced
|
| Lead | 0.021 | 0.010
|
| Mercury | 0.013 | 0.005
|
| Silver | 0.021 | 0.009
|
| Zinc | 0.073 | 0.031
|
| Gold | 0.005 | |
| Oil and Grease | 1.000 | 0.600
|
| Total suspended solids | 2.050 | 0.975
|
| pH | (
1) | (
1)
|
(e) Calciner wet air pollution control.
BPT Limitations for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/kg (pounds per million pounds) of mercury condensed
|
| Lead | 78.200 | 37.240
|
| Mercury | 46.550 | 18.620
|
| Silver | 76.340 | 31.650
|
| Zinc | 271.900 | 113.600
|
| Gold | 18.600 | |
| Oil and Grease | 3,724.000 | 2,234.000
|
| Total suspended solids | 7,634.000 | 3,631.000
|
| pH | (
1) | (
1)
|
(f) Calcine quench water.
BPT Limitations for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/kg (pounds per million pounds) of mercury condensed
|
| Lead | 7.392 | 3.520
|
| Mercury | 4.400 | 1.760
|
| Silver | 7.216 | 2.992
|
| Zinc | 25.700 | 10.740
|
| Gold | 1.760 | |
| Oil and Grease | 352.000 | 211.200
|
| Total suspended solids | 721.600 | 343.200
|
| pH | (
1) | (
1)
|
(g) Calciner stack gas contact cooling water.
BPT Limitations for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/kg (pounds per million pounds) of mercury condensed
|
| Lead | 1.743 | 0.830
|
| Mercury | 1.038 | 0.415
|
| Silver | 1.702 | 0.706
|
| Zinc | 6.059 | 2.532
|
| Gold | 0.415 | |
| Oil and Grease | 83.000 | 49.800
|
| Total suspended solids | 170.200 | 80.930
|
| pH | (
1) | (
1)
|
(h) Condenser blowdown.
BPT Limitations for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/kg (pounds per million pounds) of mercury condensed
|
| Lead | 5.796 | 2.760
|
| Mercury | 3.450 | 1.380
|
| Silver | 5.658 | 2.346
|
| Zinc | 20.150 | 8.418
|
| Gold | 1.380 | |
| Oil and Grease | 276.000 | 165.600
|
| Total suspended solids | 565.800 | 269.100
|
| pH | (
1) | (
1)
|
(i) Mercury cleaning bath water.
BPT Limitations for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/kg (pounds per million pounds) of mercury condensed
|
| Lead | 0.588 | 0.280
|
| Mercury | 0.350 | 0.140
|
| Silver | 0.574 | 0.238
|
| Zinc | 2.044 | 0.854
|
| Gold | 0.140 | |
| Oil and Grease | 28.000 | 16.800
|
| Total suspended solids | 57.400 | 27.300
|
| pH | (
1) | (
1)
|
§ 421.253 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best available technology economically achievable.
Except as provided in 40 CFR 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best available technology economically achievable:
(a) Smelter wet air pollution control.
BAT Limitations for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/troy ounce of gold and silver smelted
|
| Lead | 0.364 | 0.169
|
| Mercury | 0.195 | 0.078
|
| Silver | 0.377 | 0.156
|
| Zinc | 1.326 | 0.546
|
| Gold | 0.130 | |
(b) Silver chloride reduction spent solution.
BAT Limitations for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/troy ounce of silver reduced in solution
|
| Lead | 0.112 | 0.052
|
| Mercury | 0.060 | 0.024
|
| Silver | 0.116 | 0.048
|
| Zinc | 0.408 | 0.168
|
| Gold | 0.040 | |
(c) Electrolytic cells wet air pollution control.
BAT Limitations for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/troy ounce of gold refined electrolytically
|
| Lead | 5.544 | 2.574
|
| Mercury | 2.970 | 1.188
|
| Silver | 5.742 | 2.376
|
| Zinc | 20.200 | 8.316
|
| Gold | 1.980 | |
(d) Electrolyte preparation wet air pollution control.
BAT Limitations for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/troy ounce of silver in electrolyte produced
|
| Lead | 0.014 | 0.007
|
| Mercury | 0.008 | 0.003
|
| Silver | 0.015 | 0.006
|
| Zinc | 0.051 | 0.021
|
| Gold | 0.005 | |
(e) Calciner Wet Air Pollution Control.
BAT Limitations for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/kg (pounds per million pounds) of mercury condensed
|
| Lead | 6.160 | 2.860
|
| Mercury | 3.300 | 1.320
|
| Silver | 6.380 | 2.640
|
| Zinc | 22.440 | 9.240
|
| Gold | 2.200 | |
(f) Calcine quench water.
BAT Limitations for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/kg (pounds per million pounds) of mercury condensed
|
| Lead | 4.928 | 2.288
|
| Mercury | 2.640 | 1.056
|
| Silver | 5.104 | 2.112
|
| Zinc | 17.950 | 7.392
|
| Gold | 1.760 | |
(g) Calciner stack gas contact cooling water.
BAT Limitations for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/kg (pounds per million pounds) of mercury condensed
|
| Lead | 1.162 | 0.540
|
| Mercury | 0.623 | 0.249
|
| Silver | 1.204 | 0.498
|
| Zinc | 4.233 | 1.743
|
| Gold | 0.415 | |
(h) Condenser blowdown.
BAT Limitations for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/kg (pounds per million pounds) of mercury condensed
|
| Lead | 3.864 | 1.794
|
| Mercury | 2.070 | 0.828
|
| Silver | 4.002 | 1.656
|
| Zinc | 14.080 | 5.796
|
| Gold | 1.380 | |
(i) Mercury cleaning bath water.
BAT Limitations for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/kg (pounds per million pounds) of mercury condensed
|
| Lead | 0.392 | 0.182
|
| Mercury | 0.210 | 0.084
|
| Silver | 0.406 | 0.168
|
| Zinc | 1.428 | 0.588
|
| Gold | 0.140 | |
§ 421.254 - Standards of performance for new sources.
Any new source subject to this subpart shall achieve the following new source performance standards:
(a) Smelter wet air pollution control.
NSPS for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/troy ounce of gold and silver smelted
|
| Lead | 0.364 | 0.169
|
| Mercury | 0.195 | 0.078
|
| Silver | 0.377 | 0.156
|
| Zinc | 1.326 | 0.546
|
| Gold | 0.130 | |
| Oil and Grease | 13.000 | 13.000
|
| Total suspended solids | 19.500 | 15.600
|
| pH | (
1) | (
1)
|
(b) Silver chloride reduction spent solution.
NSPS for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/troy ounce of silver reduced in solution
|
| Lead | 0.112 | 0.052
|
| Mercury | 0.060 | 0.024
|
| Silver | 0.116 | 0.048
|
| Zinc | 0.408 | 0.168
|
| Gold | 0.040 | |
| Oil and Grease | 4.000 | 4.000
|
| Total suspended solids | 6.000 | 4.800
|
| pH | (
1) | (
1)
|
(c) Electrolytic cells wet air pollution control.
NSPS for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/troy ounce of gold refined electrolytically
|
| Lead | 5.544 | 2.574
|
| Mercury | 2.970 | 1.188
|
| Silver | 5.742 | 2.376
|
| Zinc | 20.200 | 8.316
|
| Gold | 1.980 | |
| Oil and Grease | 198.000 | 198.000
|
| Total suspended solids | 297.000 | 237.600
|
| pH | (
1) | (
1)
|
(d) Electrolyte preparation wet air pollution control.
NSPS for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/troy ounce of silver in electrolyte produced
|
| Lead | 0.014 | 0.007
|
| Mercury | 0.008 | 0.003
|
| Silver | 0.015 | 0.006
|
| Zinc | 0.051 | 0.021
|
| Gold | 0.005 | |
| Oil and Grease | 0.500 | 0.500
|
| Total suspended solids | 0.750 | 0.600
|
| pH | (
1) | (
1)
|
(e) Calciner wet air pollution control.
NSPS for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/kg (pounds per million pounds) of mercury condensed
|
| Lead | 6.160 | 2.860
|
| Mercury | 3.300 | 1.320
|
| Silver | 6.380 | 2.640
|
| Zinc | 22.440 | 9.240
|
| Gold | 2.200 | |
| Oil and Grease | 220.000 | 220.000
|
| Total suspended solids | 330.000 | 264.000
|
| pH | (
1) | (
1)
|
(f) Calcine quench water.
NSPS for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/kg (pounds per million pounds) of mercury condensed
|
| Lead | 4.928 | 2.288
|
| Mercury | 2.640 | 1.056
|
| Silver | 5.104 | 2.112
|
| Zinc | 17.950 | 7.392
|
| Gold | 1.760 | |
| Oil and Grease | 176.000 | 176.000
|
| Total suspended solids | 264.000 | 211.200
|
| pH | (
1) | (
1)
|
(g) Calciner stack gas contract cooling water.
NSPS for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/kg (pounds per million pounds) or mercury condensed
|
| Lead | 1.162 | 0.540
|
| Mercury | 0.623 | 0.249
|
| Silver | 1.204 | 0.498
|
| Zinc | 4.233 | 1.743
|
| Gold | 0.415 | |
| Oil and Grease | 41.500 | 41.500
|
| Total suspended solids | 62.250 | 49.800
|
| pH | (
1) | (
1)
|
(h) Condenser blowdown.
NSPS for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/kg (pounds per million pounds) of mercury condensed
|
| Lead | 3.864 | 1.794
|
| Mercury | 2.070 | 0.828
|
| Silver | 4.002 | 1.656
|
| Zinc | 14.080 | 5.796
|
| Gold | 1.380 | |
| Oil and Grease | 138.000 | 138.000
|
| Total suspended solids | 207.000 | 165.600
|
| pH | (
1) | (
1)
|
(i) Mercury cleaning bath water.
NSPS for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/kg (pounds per million pounds) of Mercury condensed
|
| Lead | 0.392 | 0.182
|
| Mercury | 0.210 | 0.084
|
| Silver | 0.406 | 0.168
|
| Zinc | 1.428 | 0.588
|
| Gold | 0.140 | |
| Oil and Grease | 14.000 | 14.000
|
| Total suspended solids | 21.000 | 16.800
|
| pH | (
1) | (
1)
|
§ 421.255 - [Reserved]
§ 421.256 - Pretreatment standards for new sources.
Except as provided in 40 CFR 403.7, any new source subject to this subpart which introduces pollutants into a publicly owned treatment works must comply with 40 CFR part 403 and achieve the following pretreatment standards for new sources. The mass of wastewater pollutants in primary precious metals and mercury process wastewater introduced into a POTW shall not exceed the following values:
(a) Smelter wet air pollution control.
PSNS for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/troy ounce of gold and silver smelted
|
| Lead | 0.364 | 0.169
|
| Mercury | 0.195 | 0.078
|
| Silver | 0.377 | 0.156
|
| Zinc | 1.326 | 0.546
|
| Gold | 0.130 | |
(b) Silver chloride reduction spent solution.
PSNS for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/troy ounce of silver reduced in solution
|
| Lead | 0.112 | 0.052
|
| Mercury | 0.060 | 0.024
|
| Silver | 0.116 | 0.048
|
| Zinc | 0.408 | 0.168
|
| Gold | 0.040 | |
(c) Electrolytic cells wet air pollution control.
PSNS for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/troy ounce of gold refined electrolytically
|
| Lead | 5.544 | 2.574
|
| Mercury | 2.970 | 1.188
|
| Silver | 5.742 | 2.376
|
| Zinc | 20.200 | 8.316
|
| Gold | 1.980 | |
(d) Electrolyte preparation wet air pollution control.
PSNS for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/troy ounce of silver in electrolyte produced
|
| Lead | 0.014 | 0.007
|
| Mercury | 0.008 | 0.003
|
| Silver | 0.015 | 0.006
|
| Zinc | 0.051 | 0.021
|
| Gold | 0.005 | |
(e) Calciner wet air pollution control.
PSNS for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/kg (pounds per million pounds) of mercury condensed
|
| Lead | 6.160 | 2.860
|
| Mercury | 3.300 | 1.320
|
| Silver | 6.380 | 2.640
|
| Zinc | 22.440 | 9.240
|
| Gold | 2.200 | |
(f) Calcine quench water.
PSNS for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/kg (pounds per million pounds) of mercury condensed
|
| Lead | 4.928 | 2.288
|
| Mercury | 2.640 | 1.056
|
| Silver | 5.104 | 2.112
|
| Zinc | 17.950 | 7.392
|
| Gold | 1.760 | |
(g) Calciner stack gas contact cooling water.
PSNS for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/kg (pounds per million pounds) of mercury condensed
|
| Lead | 1.162 | 0.540
|
| Mercury | 0.623 | 0.249
|
| Silver | 1.204 | 0.498
|
| Zinc | 4.233 | 1,743
|
| Gold | 0.415 | |
(h) Condenser blowdown.
PSNS for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/kg (pounds per million pounds) of mercury condensed
|
| Lead | 3.864 | 1.794
|
| Mercury | 2.070 | 0.828
|
| Silver | 4.002 | 1.656
|
| Zinc | 14.080 | 5.656
|
| Gold | 1.380 | |
(i) Mercury cleaning bath water.
PSNS for the Primary Precious Metals and Mercury Subcategory
| Pollutant or pollutant property
| Maximum for any 1 day
| Maximum for monthly average
|
|---|
| mg/kg (pounds per million pounds) of mercury condensed
|
| Lead | 0.392 | 0.182
|
| Mercury | 0.210 | 0.084
|
| Silver | 0.406 | 0.168
|
| Zinc | 1.428 | 0.588
|
| Gold | 0.140 | |
§ 421.257 - [Reserved]
authority: Secs. 301, 304 (b), (c), (e), and (g), 306 (b) and (c), 307 (b) and (c), 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) and the Water Quality Act of 1987 (the “Act”);
33 U.S.C. 1311,
1314,
c,
e,
and, 1316 (b) and
c, 1317 (b) and
c,
1318; 86 Stat. 816, Pub. L. 92-500; 91 Stat. 1567, Pub. L. 95-217; 101 Stat. 7, Pub. L. 100-4
source: 49 FR 8790, Mar. 8, 1984, unless otherwise noted.
cite as: 40 CFR 421.251