Pretreatment standards for existing sources (PSES).

Except as provided in § 425.04 and 40 CFR 403.7 and 403.13, any existing source subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment works must comply with 40 CFR part 403, and achieve the following pretreatment standards: Pollutant or pollutant property PSES Maximum for any 1 day Maximum for monthly average Milligrams per liter (mg/l) Sulfide 24 Total chromium 12 8 pH ( 1 ) ( 1 ) 1 Not less than 7.0. [47 FR 52870, Nov. 23, 1982, as amended at 61 FR 35685, July 8, 1996]