The national categorical pretreatment standards as amended and promulgated by EPA pursuant to the Act and as found at 40 CFR Chapter I, Subchapter N, Parts 405-471, are hereby incorporated and shall be enforceable under 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 of Utilities may impose equivalent concentration or mass limits [See 40 CRF 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 Director of Utilities may convert the limits to equivalent limitations expressed either as a mass of pollutant discharged per day or effluent concentration for purposes of calculating effluent limitations applicable to individual industrial users. [See 40 CFR 403.6(c)(2)].
(C) When wastewater subject to a categorical pretreatment standard is mixed with wastewater not regulated by the same standard, the Director of Utilities shall 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 the following divisions of this section. [See 40 CFR 403.15].
(1) Categorical pretreatment standards may be adjusted to reflect the presence of pollutants in the industrial user’s intake water in accordance with this section. Any industrial user wishing to obtain credit for intake pollutants must make application to the city. Upon request of the industrial user, the applicable standard will be calculated on a “net” basis (i.e., adjusted to reflect credit for pollutants in the intake water) if the requirements of division (2) below of this section are met.
(2) Criteria.
(a) Either:
1. The applicable categorical pretreatment standards contained in 40 CFR subchapter N specifically provide that they shall be applied on a net basis; or
2. The industrial user demonstrates that the control system it proposes or uses to meet the applicable categorical pretreatment standards would, if properly installed and operated, meet the standards in the absence of pollutants in the intake waters.
(b) Credit for generic pollutants such as biochemical oxygen demand (BOD), total suspended solids (TSS), and oil and grease should not be granted unless the industrial user demonstrates that the constituents of the generic measure in the user’s effluent are substantially similar to the constituents of the generic measure in the intake water or unless appropriate additional limits are placed on process water pollutants either at the outfall or elsewhere.
(c) Credit shall be granted only to the extent necessary to meet applicable categorical pretreatment standard(s), up to a maximum value equal to the influent value. Additional monitoring may be necessary to determine eligibility for credits and compliance with standard(s) adjusted under this section.
(d) Credit shall be granted only if the user demonstrates that the intake water is drawn from the same body of water as that into which the POTW discharges. The city may waive this requirement if it finds that no environmental degradation will result.
(Ord. 9399, passed 2-24-2020)