A user who falls within a regulated industrial subcategory shall comply with the National Categorical Pretreatment Standards (40 C.F.R §§ 405-471, as amended from time to time) for that particular industrial subcategory. If the National Categorical Pretreatment Standards are less stringent than the state pretreatment standards or local pollutant limitations applicable to the user, the user shall comply with the more stringent standards. The National Categorical Pretreatment Standards (Title 40 C.F.R. §§ 405-471), as amended from time to time, are hereby incorporated by reference into this chapter.
(A) Where a categorical pretreatment standard is expressed only in terms of either the mass or the concentration of a pollutant in wastewater, the Director may impose equivalent concentration or mass limits in accordance with § 52.16.
(B) When the limits in a categorical pretreatment standard are expressed only in terms of mass of pollutant per unit of production, the Director may convert the limits to equivalent limitations expressed either as mass of pollutant discharged per day or effluent concentration for purposes of calculating effluent limitations applicable to individual industrial users.
(C) When wastewater subject to a categorical pretreatment standard is mixed with wastewater not regulated by the same standard, the Director shall impose an alternate limit in accordance with 40 C.F.R. § 403.6(e).
(Ord. 5746, passed 7-1-2019)