Users must comply with the categorical pretreatment standards found at 40 CFR Chapter
I, Subchapter N, Parts 405 through 471.
(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 Wastewater or his/her designee, may impose equivalent concentration or mass limits in accordance with Subsections
(5) and
(6).
(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 Wastewater or his/her 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 industrial users.
(3) When wastewater subject to a categorical pretreatment standard is
mixed with wastewater not regulated by the same standard, the Director
of Wastewater or his/her designee shall impose an alternate limit
in accordance with 40 CFR 403.6(e).
(4) A CIU may obtain a net/gross adjustment to a categorical pretreatment
standard in accordance with the following paragraphs of this section.
a. 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 Subsection (4)b of this section
are met.
b. Criteria.
1. Either the applicable categorical pretreatment standards contained
in 40 CFR Subchapter N specifically provide that they shall be applied
on a net basis; or the industrial user demonstrates that the control
system it proposes or uses to meet applicable categorical pretreatment
standards would, if properly installed and operated, meet the Standards
in the absence of pollutants in the intake waters.
2. 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.
3. Credit shall be granted only to the extent necessary to meet the
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.
4. 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.
(5) When a categorical pretreatment standard is expressed only in terms
of pollutant concentrations, an industrial user may request that the
City of Biddeford, Maine, convert the limits to equivalent mass limits.
The determination to convert concentration limits to mass limits is
within the discretion of the Director of Wastewater or his/her designee.
The City of Biddeford, Maine, may establish equivalent mass limits
only if the industrial user meets all the conditions set forth in
Subsections (5)a1 through (5)a5 Below.
a. To be eligible for equivalent mass limits, the industrial user must:
1. Employ, or demonstrate that it will employ, water conservation methods
and technologies that substantially reduce water use 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 waste streams, 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 industrial user's request
for equivalent mass limits.
b. An industrial 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 Wastewater or his/her designee whenever production rates
are expected to vary by more than 20% from its baseline production
rates determined in Subsection (5)a3 of this section. Upon notification
of a revised production rate, the Director of Wastewater or his/her
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 Subsection (5)a1
of this section so long as it discharges under an equivalent mass
limit.
c. When developing equivalent mass limits, the Director of Wastewater
or his/her designee:
1. Will calculate the equivalent mass limit by multiplying the actual
average daily flow rate of the regulated process(es) of the industrial
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 discharger permit terms if the industrial 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
71-10. The industrial user must also be in compliance with Section
71-70 regarding the prohibition of bypass.
(6) The Director of Wastewater or his/her 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 industrial users. The conversion is at the
discretion of the Director of Wastewater or his/her designee.
(7) Once included in its permit, the industrial user must comply with the equivalent limitations developed in this Section
71-6 in lieu of the promulgated categorical standards from which the equivalent limitations were derived.
(8) Many categorical pretreatment standards specify one limit for calculating
maximum daily discharge limitations and a second limit for calculating
maximum monthly average, or four-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
limitation.
(9) Any industrial user operating under a permit incorporating equivalent
mass or concentration limits calculated from a production-based standard
shall notify the Director of Wastewater or his/her designee within
two business 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 Wastewater or his/her
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.
Users must comply with State of Maine pretreatment standards
codified as state law.
The City reserves the right to establish, by ordinance or in
individual wastewater discharge permits, more stringent standards
or requirements on discharges to the POTW consistent with the purpose
of this chapter.
No user shall ever increase the use of process water or in any
way attempt to dilute a discharge as a partial or complete substitute
for adequate treatment to achieve compliance with a discharge limitation
unless expressly authorized by an applicable pretreatment standard
or requirement. The Director of Wastewater or his/her designee may
impose mass limitations on users who are using dilution to meet applicable
pretreatment standards or requirements, or in other cases when the
imposition of mass limitations is appropriate.