(A) Where an effluent from a categorical industrial process(es) is mixed prior to treatment with wastewater other than that generated by the regulated process, fixed alternative discharge limits may be derived for the discharge permit by the Superintendent. These alternative limits shall be applied to the mixed effluent and shall be calculated using the Combined Wastestream Formula and/or Flow-Weighted Average Formula as defined in section 50.003.
(B) Where the effluent limits in a Categorical Pretreatment Standard are expressed only in terms of mass of pollutants per unit of production (production-based standard), the Superintendent may convert the limits to equivalent limitations expressed either as mass of pollutant discharged per day or of effluent concentration for purposes of calculating effluent permit limitations applicable to the permittee. The permittee shall be subject to all permit limits calculated in this manner under 40 CFR 403.6(c) and must fully comply with these alternative limits.
(C) All categorical users subject to production-based standards must report production rates annually so that alternative permit limits can be calculated if necessary. The categorical user must notify the Superintendent thirty (30) days in advance of any major change in production levels that will affect the limits for the discharge permit.
(Ord. 12-93-1, passed 12-6-93)