Statutes, codes, and regulations
Code of Federal Regulations
Title 40 - PROTECTION OF ENVIRONMENTChapter I - ENVIRONMENTAL PROTECTION AGENCYSubchapter N - EFFLUENT GUIDELINES AND STANDARDSPart 421 - NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY
Subpart W - PRIMARY PRECIOUS METALS AND MERCURY SUBCATEGORY
Section 421.256 - Pretreatment standards for new sources

40 C.F.R. § 421.256

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Current through September 30, 2024
Section 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
Lead0.3640.169
Mercury0.1950.078
Silver0.3770.156
Zinc1.3260.546
Gold0.130

(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
Lead0.1120.052
Mercury0.0600.024
Silver0.1160.048
Zinc0.4080.168
Gold0.040

(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
Lead5.5442.574
Mercury2.9701.188
Silver5.7422.376
Zinc20.2008.316
Gold1.980

(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
Lead0.0140.007
Mercury0.0080.003
Silver0.0150.006
Zinc0.0510.021
Gold0.005

(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
Lead6.1602.860
Mercury3.3001.320
Silver6.3802.640
Zinc22.4409.240
Gold2.200

(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
Lead4.9282.288
Mercury2.6401.056
Silver5.1042.112
Zinc17.9507.392
Gold1.760

(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
Lead1.1620.540
Mercury0.6230.249
Silver1.2040.498
Zinc4.2331,743
Gold0.415

(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
Lead3.8641.794
Mercury2.0700.828
Silver4.0021.656
Zinc14.0805.656
Gold1.380

(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
Lead0.3920.182
Mercury0.2100.084
Silver0.4060.168
Zinc1.4280.588
Gold0.140

40 C.F.R. §421.256