CFR > Title 40 - Protection of Environment > CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY > SUBCHAPTER N—EFFLUENT GUIDELINES AND STANDARDS (Parts 400–471) > PART 421—NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY > SUBPART I—Metallurgical Acid Plants Subcategory (§421.90 to §421.97) > 421.95—Pretreatment standards for existing sources.

421.95—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 metallurgical acid plant blowdown introduced into a POTW shall not exceed the following values:
Subpart I—Metallurgical Acid Plant—PSES
Pollutant or pollutant property Maximum for any 1 day Maximum for monthly average
mg/kg (pound per/million pounds) of 100 pct sulfuric acid capacity
Cadmium 0.511 0.204
Zinc 2.605 1.073
[50 FR 38343, Sept. 20, 1985]