Illinois Administrative Code › Title 35 - ENVIRONMENTAL PROTECTION › Part 310 - PRETREATMENT PROGRAMS › Subpart B - PRETREATMENT STANDARDS › Section 310.230 - Concentration and Mass Limits

Current through Register Vol. 48, No. 28, July 12, 2024
a)
				Pollutant discharge limits in categorical pretreatment standards will be
				expressed either as concentration or mass limits. Limits in categorical
				pretreatment standards must apply to the discharge from 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 calculating effluent limitations applicable to
				individual industrial users.
c) A
				Control Authority calculating equivalent mass-per-day limitations under
				subsection (b) must calculate such limitations by multiplying the limits in the
				standard by the industrial user's average rate of production. This average rate
				of production must be based not upon the designed production capacity, but
				rather upon a reasonable measure of the industrial user's actual long-term
				daily production during a representative year. For new sources, actual
				production must be estimated using projected production.
d) A Control Authority calculating equivalent
				concentration limitations under subsection (b) must calculate such limitations
				by dividing the mass limitations derived under subsection (c) by the average
				daily flow rate of the industrial user's regulated process wastewater. This
				average daily flow rate must be based upon a reasonable measure of the
				industrial user's actual long-term average flow rate, such as the average daily
				flow rate during the representative year.
e) When the limits in a categorical
				pretreatment standard are expressed only in terms of pollutant concentrations,
				an industrial user may request that the Control Authority convert the limits to
				equivalent mass limits. The determination to convert concentration limits to
				mass limits is within the discretion of the Control Authority. The Control
				Authority may establish equivalent mass limits only if the industrial user
				meets all the following conditions in subsections (e)(1)(A) through (e)(1)(E).
1) To be eligible for equivalent mass limits,
				the industrial user must undertake the following actions:
A) It must employ or demonstrate that it will
				employ water conservation methods and technologies that substantially reduce
				water use during the term of its control mechanism;
B) It must currently use control and
				treatment technologies adequate to achieve compliance with the applicable
				categorical pretreatment standard, and it must not have used dilution as a
				substitute for treatment;
C) It
				must 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 long-term average production
				rate must be representative of current operating conditions;
D) It must 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
E) It must have consistently
				complied with all applicable categorical pretreatment standards during the
				period before the industrial user requested equivalent mass limits.