Wisconsin Administrative Code › Department of Natural Resources › NR 100-199 - Environmental Protection - General › Chapter NR 106 - Procedures For Calculating Water Quality Based Effluent Limitations For Point Source Discharges To Surface Waters › Subchapter II - General Procedures for Effluent Limitations › Section NR 106.07 - Application of and compliance with water quality based effluent limitations in permits

Current through June 24, 2024
(1) PERMIT MONITORING FREQUENCY. The
				  department shall determine on a case-by-case basis the monitoring frequency to
				  be required for each water quality based effluent limitation in a
				  permit.
(2) GENERAL. Except as
				  provided in subs. (3) and (4), a chemical specific water quality-based effluent
				  limitation that is calculated under this chapter shall be expressed in the
				  permit as both a concentration limitation and a mass limitation unless the
				  pollutant cannot appropriately be expressed by mass or a mass limitation is
				  infeasible because the mass of the pollutant cannot be related to a measure of
				  operation. Water quality-based mass limits for discharges of chlorine are not
				  required in permits. The concentration limitation shall be expressed in units
				  of mg/L or equivalent units. The mass limitation shall be expressed in units of
				  kg/day or equivalent units. All of the following procedures shall be used when
				  calculating mass limitations:
(a) For
				  dischargers subject to ch. NR 210, an acute toxicity based concentration
				  limitation that is derived by the procedure in s.
				  NR
				  106.06 shall be converted to a mass limitation by
				  using the discharger's maximum effluent flow, expressed as a daily total flow,
				  that is anticipated to occur for 24 continuous hours during the design life of
				  the treatment facility.
(b) For all
				  other dischargers not subject to ch. NR 210, an acute toxicity based
				  concentration limitation that is derived by the procedures in s.
				  NR
				  106.06 shall be converted to a mass limitation by
				  using the discharger's maximum effluent flow, expressed as a daily total flow,
				  that has occurred for 24 continuous hours and represents normal operations.
				  When calculating a mass limitation, the department may consider a projected
				  increase in effluent flow that will occur when production is increased or
				  modified, or another wastewater source, including storm water, that is added to
				  an existing wastewater treatment facility. Limitations calculated under this
				  paragraph are subject to the antidegradation requirements of ch. NR
				  207.
(c) A chronic toxicity, human
				  health, or wildlife-based concentration limitation that is determined by the
				  procedures in s.
				  NR
				  106.06 shall be converted to a mass limitation by
				  using the same effluent flow rate that was used in s.
				  NR
				  106.06(4) (d) to calculate the
				  concentration limitation.
(d) A
				  chronic toxicity-based mass limitation that is determined by the procedures in
				  s.
				  NR 106.11
				  shall be converted to a concentration limitation by using an effluent flow rate
				  from s.
				  NR
				  106.06(4) (d).
Note:
An example of when a mass limitation is
					 infeasible is water quality-based mass limits for discharges of
					 temperature.