13.12.410 – National categorical pretreatment standards

These pretreatment requirements shall apply to all non-residential users subject to national categorical pretreatment standards, promulgated by the USEPA in accordance with Section 307(b) and (c) of the Act, currently discharging or scheduled to discharge to the City.  The categorical pretreatment standards found in 40 CFR Chapter I, Subchapter N, Parts 405-471, are hereby incorporated by reference into this chapter.

Limits in categorical pretreatment standards shall apply to the discharge from the process regulated by the standard or as otherwise specified by the standard.  Compliance with national categorical pretreatment standards is mandatory.

1. 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 Public Works or designee may impose equivalent concentration or mass limits in accordance with paragraphs B and E below and 40 CFR Section 403.6(c) unless specifically restricted by the categorical pretreatment standard.  These equivalent limitations calculated in accordance with the following requirements are deemed pretreatment standards. Users shall be required to comply with the equivalent limitations instead of the promulgated categorical standards from which the equivalent limitations were derived. An alternative pretreatment limit shall not be used if the alternative limit is below the analytical detection limit for any of the regulated pollutants.
2. When the limits in a categorical pretreatment standard are expressed only in terms of mass of pollutant per unit of production, the Director of Public Works or designee may 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 Users.  The Director of Public Works or designee calculating equivalent mass-per-day limitations shall calculate such limitations by multiplying the limits in the standard by the User’s average rate of production.  This average rate of production shall be based not upon the designed production capacity, but rather upon a reasonable measure of the User’s actual long-term daily production during a representative year.  For new sources, actual production shall be estimated using projected production. The Director of Public Works or designee calculating equivalent concentration limitations shall calculate such limitations by dividing the mass limitations by the average daily flow rate of the User’s regulated process wastewater.  This average daily flow rate must be based upon a reasonable measure of the User’s actual long-term average flow rate, such as the average daily flow rate during the representative year.
3. When wastewater subject to a categorical pretreatment standard is mixed with wastewater not regulated by the same standard, the Director of Public Works or designee shall impose an alternate limit using the combined waste stream formula in 40 CFR Section 403.6(e) provided that the regulation allows the wastewaters to be mixed and the User can supply the information necessary to allow issuance of an alternative limit.
4. A User may request and obtain a variance from USEPA of a categorical pretreatment standard if the User can prove, pursuant to the procedural and substantive provisions in 40 CFR Section 403.13, that factors relating to its discharge are fundamentally different from the factors considered by USEPA when developing the categorical  pretreatment standard.
5. When a categorical pretreatment standard is expressed only in terms of pollutant concentrations, a User may request that the Director of Public Works or designee convert the limits to equivalent mass limits.  The determination to convert concentration limits to mass limits is within the discretion of the Director of Public Works or designee.  The Director of Public Works or designee may establish equivalent mass limits only if the User meets all the conditions set forth in Sections 1.a through 1.e below.

   1. To be eligible for equivalent mass limits, the User must:

      1. Employ, or demonstrate that it will employ, water conservation methods and technologies that substantially reduce water during the term of its individual wastewater discharge permit;

      2. Currently use control and treatment technologies adequate to achieve compliance with the applicable categorical pretreatment standard, and not have used dilution as a substitute for treatment;

      3. Provide sufficient information to establish the facility’s actual average daily flow rate for all wastestreams, based on data from a continuous effluent flow monitoring device, as well as the facility’s long-term average production rate.  Both the actual average daily flow rate and the long-term average production rate must be representative of current operating conditions;

      4. Not have daily flow rates, production levels, or pollutant levels that vary so significantly that equivalent mass limits are not appropriate to control the discharge; and

      5. Have consistently complied with all applicable categorical pretreatment standards during the period prior to the User’s request for equivalent mass limits.

   2. A User subject to equivalent mass limits must:

      1. Maintain and effectively operate control and treatment technologies adequate to achieve compliance with the equivalent mass limits;

      2. Continue to record the facility’s flow rates through the use of a continuous effluent flow monitoring device;

      3. Continue to record the facility’s production rates and notify the Director of Public Works or designee whenever production rates are expected to vary by more than 20 percent from its baseline production rates determined in paragraph 1.c of this Section.  Upon notification of a revised production rate, the Director of Public Works or designee will reassess the equivalent mass limit and revise the limit as necessary to reflect changed conditions at the facility; and

      4. Continue to employ the same or comparable water conservation methods and technologies as those implemented pursuant to paragraph 1.a of this Section so long as it discharges under an equivalent mass limit.

   3. When developing equivalent mass limits, the Director of Public Works or designee:

      1. Will calculate the equivalent mass limit by multiplying the actual average daily flow rate of the regulated process(es) of the User by the concentration-based daily maximum and monthly average standard for the applicable categorical pretreatment standard and the appropriate unit conversion factor;

      2. Upon notification of a revised production rate, will reassess the equivalent mass limit and recalculate the limit as necessary to reflect changed conditions at the facility; and

      3. May retain the same equivalent mass limit in subsequent individual wastewater discharge permit terms if the User’s actual average daily flow rate was reduced solely as a result of the implementation of water conservation methods and technologies, and the actual average daily flow rates used in the original calculation of the equivalent mass limit were not based on the use of dilution as a substitute for treatment pursuant to Section 13.12.450. The User must be in compliance with Section 13.12.799 regarding the prohibition of bypass.

6. The Director of Public Works or designee may convert the mass limits of the categorical pretreatment standards of 40 CFR Parts 414, 419 and 455 to concentration limits for purposes of calculating limitations applicable to individual Users.  The conversion is at the discretion of the Director of Public Works or designee.
7. Once included in its wastewater discharge permit, the User must comply with the equivalent limitations developed in this Section in lieu of the promulgated categorical pretreatment standards from which the equivalent limitations were derived. Note: see 40 CFR Section 403.6(c)(7).
8. Many categorical pretreatment standards specify one limit for calculating maximum daily discharge limitations and a second limit for calculating maximum monthly average, or 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 limitations. Note: see 40 CFR Section 403.6(c)(8).
9. Any User operating under a permit incorporating equivalent mass or concentration limits calculated from a production-based standard shall notify the Director of Public Works or designee within two (2) work days after the User has a reasonable basis to know that the production level will significantly change within the next calendar month.  Any User not notifying the Director of Public Works or designee of such anticipated change will be required to meet the mass or concentration limits in its permit that were based on the original estimate of the long term average production rate. Note: see 40 CFR Section 403.6(c)(9).

All Users that are subject to national categorical pretreatment standards are required to file reports as required in this Ordinance, signed by an Authorized Representative per Sections 13.12.600 through 13.12.615.  These reports shall include all information that the Director of Public Works or designee deems necessary to make compliance determinations.