Current through August 31, 2023
01.
Outfalls
and Discharge Points. All permit effluent limitations, standards and
prohibitions shall be established for each outfall or discharge point of the
permitted facility, except as otherwise provided under Subsection
302.13, (Best Management
Practices,) and Subsection
303.08, (Internal Waste
Streams.) (3-24-22)
02.
Production-Based Limitations. (3-24-22)
a. In the case of POTWs, permit effluent
limitations, standards, or prohibitions shall be calculated based on design
flow. (3-24-22)
b. Except in the
case of POTWs or as provided in Subsection
303.02.b.ii., calculation
of any permit limitations, standards, or prohibitions which are based on
production (or other measure of operation) shall be based upon a reasonable
measure of actual production of the facility. (3-24-22)
i. For new sources or new dischargers, actual
production shall be estimated using projected production. The time period of
the measure of production shall correspond to the time period of the calculated
permit limitations; for example, monthly production shall be used to calculate
average monthly discharge limitations. (3-24-22)
ii. The Department may include a condition
establishing alternate permit limitations, standards, or prohibitions based
upon anticipated increased (not to exceed maximum production capability) or
decreased production levels. (3-24-22)
iii. For the automotive manufacturing
industry only, the Department shall establish an alternate condition under
303.02.b.ii., if the applicant satisfactorily demonstrates to the Department,
at the time the application is submitted, that: (3-24-22)
(1) Its actual production, as indicated in
Subsections 303.02.b. and 303.02.b.i. is
substantially below maximum production capability, and (3-24-22)
(2) There is a reasonable potential for an
increase above actual production during the duration of the permit.
(3-24-22)
iv. If the
Department establishes permit conditions under Subsection
303.02.b.ii.: (3-24-22)
(1) The permit shall require the permittee to
notify the Department at least two (2) business days prior to a month in which
the permittee expects to operate at a level higher than the lowest production
level identified in the permit. The notice shall specify: (3-24-22)
(a) The anticipated level, and the period
during which the permittee expects to operate at the alternate level; and
(3-24-22)
(b) If the notice covers
more than one (1) month, the notice shall specify the reasons for the
anticipated production level increase; and (3-24-22)
(c) New notice of discharge at alternate
levels is required to cover a period or production level not covered by prior
notice or, if during two (2) consecutive months otherwise covered by a notice,
the production level at the permitted facility does not in fact meet the higher
level designated in the notice; (3-24-22)
(2) The permittee shall comply with the
limitations, standards, or prohibitions that correspond to the lowest level of
production specified in the permit, unless the permittee has notified the
Department under Subsection
303.02.b.ii., in which case
the permittee shall comply with the lower of the actual level of production
during each month or the level specified in the notice; and (3-24-22)
(3) The permittee shall submit, with the
Discharge Monitoring Report, the level of production that actually occurred
during each month and the limitations, standards, or prohibitions applicable to
that level of production. (3-24-22)
03.
Metals. All permit effluent
limitations, standards, or prohibitions for a metal shall be expressed in terms
of total recoverable metal as defined in 40 CFR Part 136 , unless: (3-24-22)
a. An applicable effluent standard or
limitation has been promulgated under the Clean Water Act and specifies the
limitation for the metal in the dissolved or valent or total form;
(3-24-22)
b. In establishing permit
limitations on a case-by-case basis under
40 CFR
125.3, it is necessary to express the
limitation on the metal in the dissolved or valent or total form to carry out
the provisions of the Clean Water Act; or (3-24-22)
c. All approved analytical methods for the
metal inherently measure only its dissolved form (e.g., hexavalent chromium).
(3-24-22)
04.
Continuous Discharges. For continuous discharges all permit
effluent limitations, standards, and prohibitions, including those necessary to
achieve water quality standards, shall, unless impracticable, be stated as:
(3-24-22)
a. Maximum daily and average
monthly discharge limitations for all dischargers other than POTWs; or
(3-24-22)
b. Average weekly and
average monthly discharge limitations for POTWs. (3-24-22)
05.
Noncontinuous Discharges.
Discharges which are not continuous, as defined in Section
010 (Definitions), shall be
particularly described and limited, considering the following factors, as
appropriate: (3-24-22)
a. Frequency (for
example, a batch discharge shall not occur more than once every three (3)
weeks); (3-24-22)
b. Total mass
(for example, not to exceed one hundred (100) kilograms of zinc and two hundred
(200) kilograms of chromium per batch discharge); (3-24-22)
c. Maximum rate of discharge of pollutants
during the discharge (for example, not to exceed two (2) kilograms of zinc per
minute); and (3-24-22)
d.
Prohibition or limitation of specified pollutants by mass, concentration, or
other appropriate measure (for example, shall not contain at any time more than
one-tenth (0.1) mg/L zinc or more than two hundred fifty (250) grams
(one-fourth (A) kilogram) of zinc in any discharge).
(3-24-22)
06.
Mass
Limitations. (3-24-22)
a. All
pollutants limited in permits shall have limitations, standards, or
prohibitions expressed in terms of mass except: (3-24-22)
i. pH, temperature, radiation, or other
pollutants which cannot appropriately be expressed by mass; (3-24-22)
ii. When applicable standards and limitations
are expressed in terms of other units of measurement; or (3-24-22)
iii. If in establishing permit limitations on
a case-by-case basis under 40 CFR 125.3, limitations
expressed in terms of mass are infeasible because the mass of the pollutant
discharged cannot be related to a measure of operation (for example, discharges
of TSS from certain mining operations), and permit conditions ensure that
dilution will not be used as a substitute for treatment.
(3-24-22)
b. Pollutants
limited in terms of mass, may also be limited in terms of other units of
measurement, and the permit shall require the permittee to comply with both
limitations. (3-24-22)
07.
Pollutant Credits for Intake
Water. (3-24-22)
a. The following
definitions apply to the consideration of intake credits in determining
reasonable potential and establishing technology based and water quality based
effluent limits for IPDES permits. (3-24-22)
i. An intake pollutant is the amount of a
pollutant that is present in waters of the United States (including ground
water as provided in Subsection
303.07.a.iv.) at the time
water is removed from the same body of water by the discharger or other
facility supplying the discharger with intake water. (3-24-22)
ii. An intake pollutant must be from the same
body of water as the discharge in order to be eligible for an intake credit. An
intake pollutant is considered to be from the same body of water as the
discharge if the Department finds that the intake pollutant would have reached
the vicinity of the outfall point in the receiving water within a reasonable
period had it not been removed by the permittee. This finding will be
established if: (3-24-22)
(1) The background
concentration of the pollutant in the receiving water (excluding any amount of
the pollutant in the facility's discharge) is similar to that in the intake
water; (3-24-22)
(2) There is a
direct hydrological connection between the intake and discharge points; and
(3-24-22)
(3) Water quality
characteristics (e.g., temperature, pH, hardness) are similar in the intake and
receiving waters. (3-24-22)
iii. The Department may also consider other
site-specific factors relevant to the transport and fate of the pollutant to
make the finding in a particular case that a pollutant would or would not have
reached the vicinity of the outfall point in the receiving water within a
reasonable period had it not been removed by the permittee. (3-24-22)
iv. An intake pollutant from ground water may
be considered to be from the same body of water if the Department determines
that the pollutant would have reached the vicinity of the outfall point in the
receiving water within a reasonable period had it not been removed by the
permittee, except that such a pollutant is not from the same body of water if
the ground water contains the pollutant partially or entirely due to human
activity, such as industrial, commercial, or municipal operations, disposal
actions, or treatment processes. (3-24-22)
v. The determinations made under Subsections
303.07.b. and c. will be made
on a pollutant-by-pollutant and outfall-by-outfall basis. (3-24-22)
vi. These provisions do not alter
Department's obligation under Subsection
302.06.a.vii(2)
to develop effluent limitations consistent
with the assumptions and requirements of any available waste load allocations
for the discharge, that is part of a TMDL prepared by the Department and
approved by EPA pursuant to 40 CFR 130.7, or prepared by EPA
pursuant to 40 CFR
130.7(d).
(3-24-22)
b.
Consideration of intake pollutants for technology based effluent limitations:
(3-24-22)
i. Upon request of the discharger,
technology-based effluent limitations or standards shall be adjusted to reflect
credit for pollutants in the discharger's intake water if: (3-24-22)
(1) The applicable effluent limitations and
standards contained in 40 CFR Part 401 through 471 , specifically provide that
they shall be applied on a net basis; or (3-24-22)
(2) The discharger demonstrates that the
control system it proposes or uses to meet applicable technology-based
limitations and standards would, if properly installed and operated, meet the
limitations and standards in the absence of pollutants in the intake waters.
(3-24-22)
ii. Credit for
generic pollutants such as BOD or TSS should not be granted unless the
permittee demonstrates that the constituents of the generic measure in the
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.
(3-24-22)
iii. Credit shall be
granted only to the extent necessary to meet the applicable limitation or
standard, up to a maximum value equal to the influent value. Additional
monitoring may be necessary to determine eligibility for credits and compliance
with permit limits. (3-24-22)
iv.
Credit shall be granted only if the discharger demonstrates that the intake
water is drawn from the same body of water into which the discharge is made.
The Department may waive this requirement if the Department finds that no
environmental degradation will result. (3-24-22)
v. This section does not apply to the
discharge of raw water clarifier sludge generated from the treatment of intake
water. (3-24-22)
c.
Consideration of intake pollutants for water quality based effluent
limitations: (3-24-22)
i. The Department will
evaluate if there is reasonable potential for the discharge of an identified
intake pollutant to cause or contribute to an exceedance of a narrative or
numeric water quality criterion. If the Department determines that an intake
pollutant in the discharge does not have the reasonable potential to cause or
contribute to an exceedance of an applicable water quality standard, the
Department is not required to include a water quality-based effluent limit for
the identified intake pollutant in the facility's permit. (3-24-22)
ii. If a reasonable potential exists, then
water quality-based effluent limits may be established that reflect a credit
for intake pollutants where a discharger demonstrates that the following
conditions are met: (3-24-22)
(1) The facility
removes the intake water containing the pollutant from the same body of water
into which the discharge is made; (3-24-22)
(2) The ambient background concentration of
the pollutant does not meet the most stringent applicable water quality
criterion for that pollutant; (3-24-22)
(3) The facility does not alter the
identified intake pollutant chemically or physically in a manner that would
cause adverse water quality impacts to occur that would not occur if the
pollutants had not been removed from the body of water; (3-24-22)
(4) The timing and location of the discharge
would not cause adverse water quality impacts to occur that would not occur if
the identified intake pollutant had not been removed from the body of water;
(3-24-22)
(5) For the purpose of
determining water quality-based effluent limits, the facility does not increase
the identified intake pollutant concentration at the point of discharge as
compared to the pollutant concentration in the intake water.
(3-24-22)
iii. Where the
conditions in Subsection
303.07.c.i. and ii are met,
the Department may establish a water quality-based effluent limitation allowing
a facility to discharge a mass and concentration of the intake pollutant that
are no greater than the mass and concentration found in the facility's intake
water. A discharger may add mass of the pollutant to its waste stream if an
equal or greater mass is removed prior to discharge, so there is no net
addition of the pollutant in the discharge compared to the intake water.
(3-24-22)
iv. Where intake water
for a facility is provided by a municipal water supply system and the supplier
provides treatment of the raw water that removes an intake water pollutant, the
concentration of the intake water pollutant will be determined at the point
where the water enters the water supplier's distribution system.
(3-24-22)
v. Where a facility
discharges intake pollutants from multiple sources that originate from the
receiving water body and from other water bodies, the Department may derive an
effluent limit reflecting the flow-weighted amount of each source of the
pollutant provided that conditions in 303.07.c.ii. of this subsection are met
and adequate monitoring to determine compliance can be established and is
included in the permit. (3-24-22)
vi. The permit will specify how compliance
with mass and concentration-based limitations for the intake water pollutant
will be assessed. This may be done by basing the effluent limitation on
background concentration data. Alternatively, the Department may determine
compliance by monitoring the pollutant concentrations in the intake water and
in the effluent. This monitoring may be supplemented by monitoring internal
waste streams or by a Department evaluation of the use of best management
practices. (3-24-22)
vii. Effluent
limitations must be established to comply with all other applicable state and
federal laws and regulations including technology-based requirements and
anti-degradation policies. (3-24-22)
viii. When determining whether water quality
based effluent limitations are necessary, information from chemical-specific,
whole effluent toxicity and biological assessments will be considered
independently. (3-24-22)
ix. Permit
limits must be consistent with the assumptions and requirement of waste load
allocations or other provisions in a TMDL that has been approved by the EPA.
(3-24-22)
08.
Internal Waste Streams. (3-24-22)
a. When permit effluent limitations or
standards imposed at the point of discharge are impractical or infeasible,
effluent limitations or standards for discharges of pollutants may be imposed
on internal waste streams before mixing with other waste streams or cooling
water streams. In those instances, the monitoring required by Section
304 (Monitoring and Reporting
Requirements) shall also be applied to the internal waste streams.
(3-24-22)
b. Limits on internal
waste streams will be imposed only when the fact sheet sets forth the
exceptional circumstances which make such limitations necessary, such as:
(3-24-22)
i. When the final discharge point
is inaccessible (for example, under ten (10) meters of water);
(3-24-22)
ii. The wastes at the
point of discharge are so diluted as to make monitoring impracticable; or
(3-24-22)
iii. The interferences
among pollutants at the point of discharge would make detection or analysis
impracticable. (3-24-22)
09.
Disposal of Pollutants into Wells,
into POTWs, or by Land Application. (3-24-22)
a. When part of a discharger's process
wastewater is not being discharged into waters of the United States because it
is disposed into a well, into a POTW, or by land application thereby reducing
the flow or level of pollutants being discharged into waters of the United
States, applicable effluent standards and limitations for the discharge in an
IPDES permit shall be adjusted to reflect the reduced raw waste resulting from
such disposal. Effluent limitations and standards in the permit shall be
calculated by one (1) of the following methods: (3-24-22)
i. If none of the waste from a particular
process is discharged into waters of the United States, and effluent
limitations guidelines provide separate allocation for wastes from that
process, all allocations for the process shall be eliminated from calculation
of permit effluent limitations or standards; or (3-24-22)
ii. In all cases other than those described
in Subsection 303.09.a.i., effluent
limitations shall be adjusted by multiplying the effluent limitation derived by
applying effluent limitation guidelines to the total waste stream by the amount
of wastewater flow to be treated and discharged into waters of the United
States, and dividing the result by the total wastewater flow. Effluent
limitations and standards so calculated may be further adjusted under 40 CFR
Part 125 , subpart D, to make them more or less stringent if discharges to
wells, POTWs, or by land application change the character or treatability of
the pollutants being discharged to receiving waters. This method may be
algebraically expressed as:
P=(E x N)/T; where P is the permit effluent limitation,
E is the limitation derived by applying effluent guidelines to the total waste
stream, N is the wastewater flow to be treated and discharged to waters of the
United States, and T is the total wastewater flow. |
(3-24-22)
b. Subsection
303.09.a. does not apply to
the extent that promulgated effluent limitations guidelines: (3-24-22)
i. Control concentrations of pollutants
discharged but not mass; or (3-24-22)
ii. Specify a different specific technique
for adjusting effluent limitations to account for well injection, land
application, or disposal into POTWs. (3-24-22)
c. Subsection
303.09.a. does not alter a
discharger's obligation to meet any more stringent requirements established
under Sections 300
(Conditions Applicable to all Permits), 301 (Permit Conditions for Specific
Categories), 40 CFR
122.42(e), and
302 (Establishing Permit
Provisions). (3-24-22)
d. Disposal
of discharge into injection wells is regulated by: (3-24-22)
i. Idaho Department of Water Resources, in
compliance with the IDAPA 37.03.03, "Rules and Minimum Standards for the
Construction and Use of Injection Wells," for a Class I injection well; or
(3-24-22)
ii. Health District
having jurisdiction, in compliance with IDAPA 58.01.03, "Individual/Subsurface
Sewage Disposal Rules," for a Class V injection well.
(3-24-22)
e. Disposal of
discharge onto the surface of the land is regulated by the Department under
IDAPA 58.01.17, "Recycled Water Rules." (3-24-22)