13.90.060 National categorical pretreatment standards.
The categorical pretreatment standards found at 40 CFR Chapter I, Subchapter N, Parts 405 through 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 Public Works Director may impose equivalent concentration or mass limits in accordance with PMC 13.90.090, 13.90.100, and 13.90.110 (see 40 CFR § 403.6(c)).
(2) When categorical pretreatment standards are expressed in terms of a mass of pollutant which may be discharged per unit of production, the Public Works Director may either impose limits based on mass or equivalent effluent concentrations. The user must supply appropriate actual or projected long term production rates for the unit of production specified in order to facilitate this process (See 40 CFR § 403.6(c)(2)).
(3) The Public Works Director may allow wastewater subject to a categorical pretreatment standard to be mixed with other wastewaters prior to treatment. In such cases, the user shall identify all categorical wastestreams and provide sufficient information on each noncategorical wastestream to determine whether it should be considered dilute for each pollutant. Absent information showing that noncategorical wastestreams contain the pollutant in question at levels above that of the supply water, such wastestreams shall be considered dilute. In such situations, the Public Works Director shall apply the CWF as found at 40 CFR § 403.6(e) to determine appropriate limits.
(4) A CIU may request an adjustment to a categorical standard to reflect the presence of pollutants in the industrial user’s intake water when its water source is from the same body of water that the POTW discharges into.
(a) Any CIU wishing to obtain credit for intake pollutants must include, in their permit application, sample data showing influent water pollutant levels which form the basis for the credit requested in their permit application.
(b) Unless the categorical standard was written to be applied on a net basis, the information supplied by the CIU must also demonstrate that the treatment system it proposes or uses to meet the categorical standards would, if properly installed and operated, meet the standards in the absence of pollutants in the intake waters.
(c) In response to an acceptable application, the Public Works Director may adjust the categorical standards to the extent necessary to meet the applicable categorical pretreatment standard(s), up to a maximum value equal to the influent pollutant concentration.
(d) The Public Works Director may waive the requirement for the intake water to be drawn from the same body of water the POTW discharges to if the Public Works Director determines that no environmental degradation will result.
(5) When a categorical pretreatment standard is expressed only in terms of pollutant concentrations, an industrial user may request that the City convert the limits to equivalent mass limits. The City may establish equivalent mass limits if the industrial user meets all of the conditions set forth below.
(a) To be eligible for equivalent mass limits, the industrial user must submit information with its permit application or permit modification request which:
(i) Shows it has a pretreatment system which has consistently met all applicable pretreatment standards and maintained compliance without using dilution;
(ii) Describes the water-conserving practices and technologies it employs, or will employ, to substantially reduce water use during the term of its permit;
(iii) Includes the facility’s actual average daily flow rate for all wastestreams from continuous effluent flow metering;
(iv) Determines an appropriate unit of production, and provides the present and long-term average production rates for this unit of production;
(v) Shows that long-term average flow and production is representative of current operating conditions;
(vi) Shows that its daily flow rates, production levels, or pollutant levels do not vary so much that equivalent mass limits would be inappropriate; and
(vii) Shows the daily and monthly average pollutant allocations currently provided based on the proposed unit of production.
(b) An industrial user subject to equivalent mass limits must:
(i) Maintain and effectively operate control and treatment technologies adequate to achieve compliance with the equivalent mass limits;
(ii) Continue to record the facility’s flow by continuous effluent flow monitoring;
(iii) Continue to record the facility’s production rates;
(iv) Notify the Public Works Director if production rates are expected to vary by more than 20 percent from the baseline production rates submitted according to subsection (5)(a)(iv) of this section. The Public Works Director may reassess and revise equivalent limits as necessary to reflect changed conditions; and
(v) Continue to employ the same or comparable water conservation methods and technologies as those implemented pursuant to subsection (5)(a)(ii) of this section so long as it discharges under an equivalent mass limit.
(c) Equivalent mass limits:
(i) Will not exceed the product of the actual average daily flow from the regulated process or processes of the user, the applicable concentration-based daily maximum standard, the applicable concentration-based monthly average standard, and combined with the appropriate unit conversion factor;
(ii) May be reassessed and the permit revised upon notification of a revised production rate, as necessary to reflect changed conditions at the facility; and
(iii) May be retained in subsequent permits if the user’s production basis and other information submitted in subsection (5)(a) of this section are verified in their reapplication. The user must also be in compliance with Section 13.3 regarding the prohibition of bypass.
(6) The Public Works Director may convert the mass limits of the categorical pretreatment standards of 40 CFR Parts 414 (organic chemicals), 419 (petroleum refining), and 455 (pesticide formulating, packaging and repackaging) to concentration limits in permits for such users. In such cases, the Public Works Director will document the basis and the determination that dilution is not being substituted for treatment in the permit fact sheet.
(7) The Public Works Director is obliged under federal regulations to make the documentation of how any equivalent limits were derived (concentration to mass limits or vice versa) publicly available.
(8) Once incorporated into its permit, the user must comply with the equivalent limits in lieu of the categorical standards from which they were derived.
(9) The same production and flow estimates shall be used in calculating equivalent limits for the monthly (or multiple day average) and the maximum day limits.
(10) Users subject to permits with equivalent mass or concentration limits calculated from a production-based standard shall notify the Public Works Director if production will significantly change. This notification is required within two business days after the user has a reasonable basis to know that production will significantly change in the next calendar month. Users who fail to notify the Public Works Director of such anticipated changes must meet the more stringent of the equivalent limits or the user’s prior limits. [Ord. 4169 § 1, 2014; Code 1970 § 13.62.020(B).]