Users must comply with the categorical pretreatment standards found at 40 CFR chapter I, subchapter N, parts 405 through 471.
A. Where a categorical pretreatment standard is expressed only in terms of either the mass or the concentration of a pollutant in wastewater, the public works coordinator may impose equivalent concentration or mass limits in accordance with 40 CFR 403.6(c).
B. When the limits in a categorical pretreatment standard are expressed only in terms of mass of pollutant per unit of production, the public works coordinator may, as per 40 CFR 403.6(c)(2), 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. Once included in its permit, the industrial user must comply with the equivalent limitations developed in lieu of the promulgated categorical pretreatment standards from which the equivalent limitations were derived.
C. When wastewater subject to a categorical pretreatment standard is mixed with wastewater not regulated by the same standard, the public works coordinator may impose an alternate limit in accordance with 40 CFR 403.6(e).
D. A CIU may obtain a net/gross adjustment to a categorical pretreatment standard in accordance with 40 CFR 403.15.
E. Many categorical pretreatment standards specify one limit for calculating maximum daily discharge limitations and a second limit for calculating maximum monthly average, or four (4) day average, limitations. Where such standards are being applied, the same production or flow figure shall be used in calculating both the average and the maximum equivalent limitation, as per 40 CFR 403.6(c)(8). (Ord. 701, 12-8-2020)