Pretreatment standards for existing sources (PSES).

Except as provided in 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) Total chromium 19 12 pH ( 1 ) ( 1 ) 1 Within the range 6.0 to 10.0.