Regulations last checked for updates: May 19, 2024

Title 40 - Protection of Environment last revised: May 16, 2024
§ 421.263 - 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) Furnace wet air pollution control.

BAT Limitations for the Secondary Precious Metals Subcategory

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of precious metals, including silver, incinerated or smelted
Copper5.7602.745
Cyanide (total)0.9000.360
Zinc4.5901.890
Combined metals1.350
Ammonia (as N)599.900263.700

(b) Raw material granulation.

BAT Limitations for the Secondary Precious Metals Subcategory

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of precious metals in the granulated raw material
Copper0.8190.390
Cyanide (total)0.1280.051
Zinc0.6530.269
Combined metals0.192
Palladium0.064
Platinum0.064
Ammonia (as N)85.31037.500

(c) Spent plating solutions.

BAT Limitations for the Secondary Precious Metals Subcategory

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/liter of spent plating solution used as a raw material
Copper1.2800.610
Cyanide (total)0.2000.080
Zinc1.0200.420
Gold
Combined metals0.300
Ammonia (as N)133.30058.600

(d) Spent cyanide stripping solutions.

BAT Limitations for the Secondary Precious Metals Subcategory

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of gold produced by cyanide stripping
Copper4.7362.257
Cyanide (total)0.7400.296
Zinc3.7741.554
Combined metals1.110
Ammonia (as N)493.200216.800

(e) Refinery wet air pollution control 2.

2 This allowance applies to either acid or alkaline wet air pollution control scrubbers. If both acid and alkaline wet air pollution control scrubbers are present in a particular facility the same allowance applies to each.

BAT Limitations for the Secondary Precious Metals Subcategory

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of precious metals, including silver, produced in refinery
Copper1.2800.610
Cyanide (total)0.2000.080
Zinc1.0200.420
Combined metals0.300
Ammonia (as N)133.30058.600

(f) Gold solvent extraction raffinate and wash water.

BAT Limitations for the Secondary Precious Metals Subcategory

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of gold produced by solvent extraction
Copper0.8060.384
Cyanide (total)0.1260.050
Zinc0.6430.265
Combined metals0.189
Ammonia (as N)83.98036.920

(g) Gold spent electrolyte.

BAT Limitations for the Secondary Precious Metals Subcategory

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of gold produced by electrolysis
Copper0.01110.0053
Cyanide (total)0.00170.0007
Zinc0.00890.0037
Combined metals0.0030
Ammonia (as N)1.16000.5100

(h) Gold precipitation and filtration.

BAT Limitations for the Secondary Precious Metals Subcategory

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of gold precipitated
Copper5.6322.684
Cyanide (total)0.8800.352
Zinc4.4881.848
Combined metals1.320
Ammonia (as N)586.500257.800

(i) Platinum precipitation and filtration.

BAT Limitations for the Secondary Precious Metals Subcategory

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of platinum precipitated
Copper6.6563.172
Cyanide (total)1.0400.416
Zinc5.3042.184
Combined metals0.560
Ammonia (as N)693.200304.700

(j) Palladium precipitation and filtration.

BAT Limitations for the Secondary Precious Metals Subcategory

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of palladium precipitated
Copper7.6803.660
Cyanide (total)1.200.480
Zinc6.1202.520
Combined metals1.800
Ammonia (as N)799.800351.600

(k) Other platinum group metals precipitation and filtration.

BAT Limitations for the Secondary Precious Metals Subcategory

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of other platinum group metals precipitated
Copper6.6563.172
Cyanide (total)1.0400.416
Zinc5.3042.184
Combined metals1.560
Ammonia (as N)693.200304.700

(l) Spent solutions from PGC salt production.

BAT Limitations for the Secondary Precious Metals Subcategory

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of gold contained in PGC product
Copper1.1520.549
Cyanide (total)0.1800.072
Zinc0.9180.378
Combined metals0.270
Ammonia (as N)120.00052.740

(m) Equipment and floor wash.

BAT Limitations for the Secondary Precious Metals Subcategory

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of precious metals, including silver, produced in refinery
Copper0.0000.000
Cyanide (total)0.0000.000
Zinc0.0000.000
Combined metals0.000
Ammonia (as N)0.0000.000

(n) Preliminary treatment.

BAT Limitations for the Secondary Precious Metals Subcategory

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
Mg/troy ounce of total precious metals produced through this operation
Copper64.00030.500
Cyanide (Total)10.0004.000
Zinc51.00021.000
Combined metals15.000
Ammonia (as N)6665.0002930.000
[50 FR 38365, Sept. 20, 1985, as amended at 55 FR 31706, Aug. 3, 1990; 55 FR 36932, Sept. 7, 1990]
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) andc, 1317 (b) andc,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 421.263