Regulations last checked for updates: May 19, 2024

Title 40 - Protection of Environment last revised: May 16, 2024
§ 421.125 - Pretreatment standards for existing sources.

Except as provided in 40 CFR 403.7 and 403.13, any existing 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 existing sources. The mass of wastewater pollutants in secondary silver process wastewater introduced into a POTW must not exceed the following values.

(a) Subpart L—Film Stripping.

PSES

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of silver from film stripping
Copper64.45030.720
Zinc51.36021.150
Ammonia (as N)6,712.0002,951.000

(b) Subpart L—Film Stripping Wet Air Pollution Control and Precipitation and Filtration of Film Stripping Solutions Wet Air Pollution Control.

PSES

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of silver from precipitation and filtration of film stripping solutions
Copper1.242.592
Zinc.990.408
Ammonia (as N)129.30056.840

(c) Subpart L—Precipitation and Filtration of Film Stripping Solutions.

PSES

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of silver precipitated
Copper73.69035.120
Zinc58.72024.180
Ammonia (as N)7,674.0003,374.000

(d) Subpart L—Precipitation and Filtration of Photographic Solutions.

PSES

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of silver precipitated
Copper34.04816.226
Zinc27.13211.172
Ammonia (as N)3,545.0001,559.000

(e) Subpart L—Precipitation and Filtration of Photographic Solutions Wet Air Pollution Control.

PSES

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of silver from precipitation and filtration of photographic solutions
Copper15.5407.406
Zinc12.3805.099
Ammonia (as N)1,618.000711.400

(f) Subpart L—Electrolytic Refining.

PSES

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of silver from electrolytic refining
Copper.973.464
Zinc.775.319
Ammonia (as N)101.30044.540

(g) Subpart L—Furnace Wet Air Pollution Control.

PSES

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of silver roasted, smelted, or dried
Copper.000.000
Zinc.000.000
Ammonia (as N).000.000

(h) Subpart L—Leaching.

PSES

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of silver produced from leaching
Copper.110.053
Zinc.088.036
Ammonia (as N)11.4705.040

(i) Subpart L—Leaching Wet Air Pollution Control and Precipitation of Nonphotographic Solutions Wet Air Pollution Control.

PSES

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of silver produced from leaching or silver precipitated
Copper5.6712.703
Zinc4.5191.861
Ammonia (as N)590.500259.600

(j) Subpart L—Precipitation and Filtration of Nonphotographic Solutions.

PSES

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of silver precipitated
Copper3.9301.873
Zinc3.1321.290
Ammonia (as N)409.300179.900

(k) Subpart L—Floor and Equipment Washdown.

PSES

Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/troy ounce of silver production
Copper.000.000
Zinc.000.000
Ammonia (as N).000.000
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 421.125