National Categorical Pretreatment Standards.

A. The categorical pretreatment standards found in 40 CFR Chapter I, Subchapter N, Parts 405-471, are hereby incorporated.(1) Where a categorical pretreatment standard is expressed only in terms of either the mass or the concentration of a pollutant in wastewater, the Chief Plant Operator and/or Superintendent of Sewers may impose equivalent concentration or mass limits in accordance with 40 CFR 403.6(c)(1)-(2).(2) When wastewater subject to a categorical pretreatment standard is mixed with wastewater not regulated by the same standard prior to treatment, the Chief Plant Operator and/or Superintendent of Sewers may impose an alternate limit using the combined waste stream formula in 40 CFR 403.6(e).(3) A user may obtain a variance from EPA Region 2 from a categorical pretreatment standard if the user can prove, pursuant to the procedural and substantive provisions in 40 CFR 403.13, that factors relating to its discharge are fundamentally different from the factors considered by EPA when developing the categorical pretreatment standard.(4) A user may obtain a net gross adjustment to a categorical standard in accordance with 40 CFR 403.15.B.

Upon the promulgation of new or revised federal categorical pretreatment standards for a particular industrial subcategory, the federal standard, if more stringent than limitations imposed under this Sewer Use Law for sources in that subcategory shall immediately supersede the limitation imposed under this Sewer Use Law.