Current through Register Vol. 6, March 22, 2024
(1) All permit
effluent limitations, standards, and prohibitions must be established for each
outfall or discharge point of the permitted facility, except as otherwise
provided under ARM
17.30.1344 (40 CFR
122.44(k)) (BMP's where
limitations are infeasible) and (10) (limitations on internal waste
streams).
(2) Production-based
limitations.
(a) In the case of POTW's,
permit limitations, standards, or prohibitions must be calculated based on
design flow.
(b) Except in the case
of POTW's, or as provided in (3), calculation of any permit limitations,
standards, or prohibitions which are based on production (or other measure of
operation) must be based not upon the designed production capacity but rather
upon a reasonable measure of actual production of the facility. For new sources
or new dischargers, actual production must be estimated using projected
production. The time period of the measure of production must correspond to the
time period of the calculated permit limitations; for example, monthly
production must be used to calculate average monthly discharge
limitations.
(3) 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.
(4) If the department establishes permit
conditions under (3):
(a) The permit must
require the permittee to notify the department at least two 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 must specify the
anticipated level and the period during which the permittee expects to operate
at the alternate level. If the notice covers more than one month, the notice
must specify the reasons for the anticipated production level increase. 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 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.
(b) 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 (a), 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.
(c) The
permittee shall submit with the DMR the level of production that actually
occurred during each month and the limitations, standards, or prohibitions
applicable to that level of production.
(5) All permit effluent limitations,
standards, or prohibitions for a metal must be expressed in terms of "total
recoverable metal" as defined in 40 CFR Part 136 unless:
(a) an applicable effluent standard or
limitation has been promulgated under the Act and specifies the limitation for
the metal in the dissolved or valent or total form; or
(b) in establishing permit limitations on a
case-by-case basis under ARM
17.30.1203, 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 Act; or
(c) all approved analytical methods for the
metal inherently measure only its dissolved form (e.g., hexavalent
chromium).
(6) For
continuous discharges all permit effluent limitations, standards, and
prohibitions, including those necessary to achieve water quality standards,
must unless impracticable be stated as:
(a)
maximum daily and average monthly discharge limitations for all dischargers
other than publicly owned treatment works; and
(b) average weekly and average monthly
discharge limitations for POTW's.
(7) Discharges which are not continuous, as
defined in ARM
17.30.1304(12),
must be particularly described and limited, considering the following factors,
as appropriate:
(a) frequency (for example, a
batch discharge must not occur more than once every three weeks);
(b) total mass (for example, not to exceed
100 kilograms of zinc and 200 kilograms of chromium per batch
discharge);
(c) maximum rate of
discharge of pollutants during the discharge (for example, not to exceed two
kilograms of zinc per minute); and
(d) prohibition or limitation of specified
pollutants by mass, concentration, or other appropriate measure (for example,
must not contain at any time more than 0.1 mg/l zinc or more than 250 grams
(1/4 kilogram) of zinc in any discharge).
(8) Mass limitations:
(a) All pollutants limited in permits must
have limitations, standards, or prohibitions expressed in terms of mass except:
(i) for pH, temperature, radiation, or other
pollutants which cannot appropriately be expressed by mass;
(ii) when applicable standards and
limitations are expressed in terms of other units of measurement; or
(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 total suspended solids
(TSS) from certain mining operations), and permit conditions ensure that
dilution will not be used as a substitute for treatment.
(b) Pollutants limited in terms of mass
additionally may be limited in terms of other units of measurement, and the
permit must require the permittee to comply with both limitations.
(9) Pollutants in intake water:
(a) Upon request of the discharger,
technology-based effluent limitations or standards must be adjusted to reflect
credit for pollutants in the discharger's intake water if:
(i) the applicable effluent limitations and
standards contained in 40 CFR chapter 1, subchapter N, specifically provide
that they must be applied on a net basis; or
(ii) 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.
(b) Credit for
generic pollutants such as biochemical oxygen demand (BOD) or total suspended
solids (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.
(c)
Credit may be granted only to the extent necessary to meet the applicable
limitation or standards, 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.
(d)
Credit may 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 it finds that no environmental
degradation will result.
(e) This
rule does not apply to the discharge of raw water clarifier sludge generated
from the treatment of intake water.
(10) Internal waste streams:
(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 ARM 17.30.1344,
in accordance with 40 CFR
122.44(i), must also be
applied to the internal waste streams.
(b) Limits on internal waste streams may be
imposed only when the fact sheet under ARM
17.30.1371 sets forth the
exceptional circumstances which make such limitations necessary, such as when
the final discharge point is inaccessible (for example, under 10 meters of
water), the wastes at the point of discharge are so diluted as to make
monitoring impracticable, or the interferences among pollutants at the point of
discharge would make detection or analysis impracticable.
(11) Permit limitations and standards
concerning disposal of pollutants into wells, POTW's, or by land application
must be calculated as provided in ARM
17.30.1354.
(12) The department adopts and incorporates
by reference:
(a)
40 CFR
122.44(j)(2), which is a
federal agency rule setting forth a requirement for the submittal by a publicly
owned treatment work (POTW) of a local pretreatment program;
(b)
40 CFR
122.45(b)(2)(ii)(A) which is
a federal agency rule setting forth the availability of alternate permit
limitations, standards, or prohibitions based on varying production
levels;
(c)
40 CFR
136, which is a series of federal agency
rules setting forth guidelines for testing procedures for the analysis of
pollutants;
(d)
40 CFR
125.3, which is a federal agency rule setting
forth technology-based treatment requirements for point source
dischargers;
(e) 40 CFR chapter 1,
subchapter N, which is a series of federal agency rules setting forth effluent
guidelines and standards for point source dischargers; and
(f)
40 CFR
122.44(i), which is a
federal agency rule setting forth monitoring requirements for point source
dischargers.
AUTH:
75-5-201,
75-5-401, MCA; IMP:
75-5-401,
MCA