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 process wastewater pollutants into a POTW shall comply with ch. NR 211 and achieve the following PSES. The following mass limitations are provided as guidance for cases where the POTW finds that mass limitations are necessary.