14.10.060 National Categorical Pretreatment Standards.
The Categorical Pretreatment Standards found at 40 CFR Chapter I, Subchapter N, Parts 405 471 are hereby incorporated.
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 may impose equivalent concentration or mass limits in accordance with Section 14.10.060(D) and Section 14.10.060(E) and 40 CFR Part 403.6(c).
B. When Categorical Pretreatment Standards are expressed in terms of a mass of pollutant which may be discharged per unit of production, the 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 pursuant to 40 CFR Part 403.6(c)(2).
C. The 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 Director shall apply the combined wastestream formula as found at 40 CFR Part 403.6(e) to determine appropriate limits.
D. 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.
1. To be eligible for equivalent mass limits, the Industrial User must submit information with its permit application or permit modification request which:
a. Shows it has a pretreatment system which has consistently met all applicable Pretreatment Standards and maintained compliance without using dilution;
b. Describes the water conserving practices and technologies it employs, or will employ, to substantially reduce water use during the term of its permit;
c. Includes the facility’s actual average daily flow rate for all waste streams from continuous effluent flow metering;
d. Determines an appropriate unit of production, and provides the present and long-term average production rates for this unit of production;
e. Shows that long-term average flow and production are representative of current operating conditions;
f. Shows that its daily flow rates, production levels, or pollutant levels do not vary so much that equivalent mass limits would be inappropriate; and
g. Shows the daily and monthly average pollutant allocations currently provided based on the proposed unit of production.
2. An Industrial User subject to equivalent mass limits must:
a. Maintain and effectively operate control and treatment technologies adequate to achieve compliance with the equivalent mass limits;
b. Continue to record the facility’s flow by continuous effluent flow monitoring;
c. Continue to record the facility’s production rates;
d. Notify the Director if production rates are expected to vary by more than twenty (20) percent from the baseline production rates submitted according to Section 14.10.060(D)(1)(d). The Director may reassess and revise equivalent limits as necessary to reflect changed conditions; and
e. Continue to employ the same or comparable water conservation methods and technologies as those implemented pursuant to Section 14.10.060(D)(1)(b) so long as it discharges under an equivalent mass limit.
3. Equivalent mass limits:
a. Will not exceed the product of the actual average daily flow from regulated process(es) of the User and the applicable concentration-based daily maximum and monthly average standards (and the appropriate unit conversion factor);
b. May be reassessed and the permit revised upon notification of a revised production rate, as necessary to reflect changed conditions at the facility; and
c. May be retained in subsequent permits if the User’s production basis and other information submitted in Section 14.10.060(D)(1) is verified in their reapplication. The User must also be in compliance with Section 14.10.700 regarding the prohibition of bypass.
E. The 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 Director will document the basis and the determination that dilution is not being substituted for treatment in the permit fact sheet.
F. The 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.
G. Once incorporated into its permit, the User must comply with the equivalent limits in lieu of the Categorical Standards from which they were derived.
H. The same production and flow estimates shall be used in calculating equivalent limits for the monthly (or multiple day average) and the maximum day.
I. Users subject to permits with equivalent mass or concentration limits calculated from a production based standard shall notify the 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 Director of such anticipated changes must meet the more stringent of the equivalent limits or the User’s prior limits. (Ord. M-3970 §2, 2010)