Pretreatment standards for existing sources

Pretreatment standards for existing sources. Pretreatment standards for existing sources. Except as provided in ss. NR 211.13 and 211.14 , any existing source subject to this subchapter which introduces pollutants into a publicly owned treatment works shall comply with ch. NR 211 and achieve the following pretreatment standards for existing sources. Grinding scrubber operations may not discharge process wastewater pollutants to a POTW.