Direct dischargers that have had national pollutant discharge elimination system permits
modified or reissued to provide a variance pursuant to section 301(i)(2) of the clean water
act shall be required to meet compliance dates set in any applicable categorical
pretreatment standard. Existing sources that become nondomestic users subsequent to the
promulgation of an applicable categorical pretreatment standard shall be considered
existing nondomestic users, except where the sources meet the definition of a new source
as defined in R 323.2302(r).
(4) New sources shall install, have in operating condition, and start up all pollution control
equipment required to meet applicable pretreatment standards before beginning to
discharge. Within the shortest feasible time, but not more than 90 days, new sources shall
meet all applicable pretreatment standards. Construction on a site at which an existing
source is located results in a modification rather than a new source if the construction does
not create a new building, structure, facility, or installation meeting the criteria of R
323.2302(r)(ii) or (iii), but otherwise alters, replaces, or adds to existing process or
production equipment. Construction of a new source as defined in R 323.2302(r) has
commenced if the owner or operator has done either of the following:
(a) Begun, or caused to begin, as part of a continuous onsite construction program, either
of the following:
(i) Any placement, assembly, or installation of facilities or equipment.
(ii) Significant site preparation work, including clearing, excavation, or removal of
existing buildings, structures, or facilities that is necessary for the placement, assembly, or
installation of new source facilities or equipment.
(b) Entered into a binding contractual obligation for the purchase of facilities or
equipment that is intended to be used in the operation within a reasonable time. Options to
purchase or contracts that can be terminated or modified without substantial loss and
contracts for feasibility, engineering, and design studies do not constitute a contractual
obligation under this subdivision.
(5) All of the following provisions apply to concentration and mass limits:
(a) Pollutant discharge limits in categorical pretreatment standards will be expressed
either as concentration or mass limits. Where possible, where concentration limits are
specified in standards, equivalent mass limits will be provided so that local, state, or federal
authorities responsible for enforcement may use either concentration or mass limits. Limits
in categorical pretreatment standards shall apply to the effluent of the process regulated by
the standard or as otherwise specified by the standard.
(b) When the limits in a categorical pretreatment standard are expressed only in terms of
mass of pollutant per unit of production, the control authority 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
nondomestic users.
(c) A control authority calculating equivalent mass-per-day limitations under subdivision
(b) of this subrule shall calculate the limitations by multiplying the limits in the standard
by the nondomestic user's average rate of production. The average rate of production shall
be based not upon the designed production capacity, but rather upon a reasonable measure
of the nondomestic user's actual long-term daily production, such as the average daily
production during a representative year. For new sources, actual production shall be
estimated using projected production.
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