NR 106.07(5m)(b) (b) If there are fewer than 10 representative data points the CV shall be set equal to 0.6.

NR 106.07(5m)(c) (c) When calculating the CV in par. (a) a monitoring result less than the limit of detection may be assigned a value of zero. If the effluent limitation is less than the limit of detection, the department may substitute a value other than zero for results less than the limit of detection, after considering the number of monitoring results that are greater than the limit of detection and if warranted when applying appropriate statistical techniques.

NR 106.07(6) (6) limitations below the level of detection or quantification. When the water quality based effluent limitation for any substance in a permit is less than the limit of detection or the limit of quantitation, the following conditions shall apply:

NR 106.07(6)(a) (a) The permittee shall perform monitoring required in the permit using an acceptable analytical methodology for that substance in the effluent which produces the lowest limit of detection and limit of quantitation.

NR 106.07(6)(b) (b) The permittee shall determine the limit of detection and limit of quantitation using a method specified by the department.

NR 106.07(6)(c) (c) Compliance with concentration and mass limitations shall be determined as follows:

NR 106.07(6)(c)1. 1. When the water quality based effluent limitation is less than the limit of detection, effluent levels less than the limit of detection are in compliance with the effluent limitation.

NR 106.07(6)(c)2. 2. When the water quality based effluent limitation is less than the limit of detection, effluent levels greater than the limit of detection, but less than the limit of quantitation are in compliance with the effluent limitation except when analytically confirmed and statistically confirmed by a sufficient number of analyses of multiple samples and use of appropriate statistical techniques. The department may require in a permit additional monitoring when effluent levels are between the limit of detection and the limit of quantitation.

NR 106.07(6)(c)3. 3. When the water quality based effluent limitation is greater than the limit of detection, but less than the limit of quantitation effluent levels less than the limit of detection or less than the limit of quantitation are in compliance with the effluent limitation.

NR 106.07(6)(d) (d) When the water quality based effluent limitation is expressed in the permit as a daily maximum or average mass limitation, compliance is determined according to par. (c) after converting the limit of detection and limit of quantitation to mass values using appropriate conversion factors and the actual daily effluent flow, or actual average effluent flow for the averaging period.

NR 106.07(6)(e) (e) Except as provided in this paragraph, when calculating an average or mass discharge level for determining compliance with an effluent limitation according to the provisions of par. (c), a monitoring result less than the limit of detection may be assigned a value of zero. If the effluent limitation is less than the limit of detection, the department may substitute a value other than zero for results less than the limit of detection, after considering the number of monitoring results that are greater than the limit of detection and if warranted when applying appropriate statistical techniques.

NR 106.07(6)(f) (f) Unless the permittee can demonstrate continuous compliance with the limit, the department shall include a condition in the permit requiring the permittee to develop and implement or update and implement a cost-effective pollutant minimization program as specified in s. NR 106.04 (5).

NR 106.07(7) (7) Whole effluent toxicity as alternative limit. The department may establish a whole effluent toxicity limitation according to s. NR 106.09 as an alternative to a chemical specific water quality-based effluent limitation based on a fish and aquatic life secondary acute or secondary chronic value determined according to ss. NR 105.05 (4) and 105.06 (6). The alternative whole effluent toxicity limitation shall meet all the following conditions:

NR 106.07(7)(a) (a) The fathead minnow (Pimephales promelas) or the cladoceran Ceridaphnia dubia were represented in the toxicological database used to generate the secondary value:

NR 106.07(7)(b) (b) The permittee has requested the alternative whole effluent toxicity limitation; and

NR 106.07(7)(c) (c) Whole effluent toxicity testing required in the permit shall be conducted at a frequency to be determined by the department, but at least once every 3 months during the entire term of the permit.

NR 106.07(8) (8) Secondary values and studies within the Great Lakes basin. If the effluent limitation based on a secondary value is established in a permit, a permittee discharging to the Great Lakes as defined in s. NR 102.22 (5) may request that additional time be added to the compliance schedule, according to s. NR 106.117 (2), for the permittee to conduct studies, other than studies for site-specific criteria under s. NR 105.02 (1), that are needed to propose a revision to the secondary value upon which the effluent limitation is based. During this time, the permittee may provide additional data necessary to either refine the secondary value or calculate a water quality criterion.

NR 106.07(9) (9) Wet weather mass limitations. In addition to the mass limitation calculated under sub. (2) (c), for a discharger subject to ch. NR 210 and which discharges on a year-around basis, the department shall include in the permit an alternative wet weather mass limitation. For purposes of compliance, this alternative wet weather mass limitation shall apply when the mass discharge level exceeds the mass limitation calculated under sub. (2) (c) and when the permittee demonstrates to the satisfaction of the department that the discharge exceedance is caused by and occurs during a wet weather event. For purposes of this subsection, a wet weather event occurs during and immediately following periods of precipitation or snowmelt, including but not limited to rain, sleet, snow, hail or melting snow, during which water from the precipitation, snowmelt or elevated groundwater enters the sewerage system through infiltration or inflow, or both. In calculating this alternative wet weather mass limitation, the department shall use the concentration limit determined by the procedures in s. NR 106.06, the appropriate conversion factor and the appropriate effluent flow given in either par. (a) or (b).

NR 106.07(9)(a) (a) For effluent limitations based on aquatic life chronic toxicity criteria or secondary chronic values, the maximum effluent flow, expressed as a daily average, that is anticipated to occur for 7 continuous days during the design life of the treatment facility.

NR 106.07(9)(b) (b) For effluent limitations based on wildlife, human threshold or human cancer criteria or secondary values, or taste and odor criteria, the maximum effluent flow, expressed as a daily average, that is anticipated to occur for 30 continuous days during the design life of the treatment facility.

NR 106.07(10) (10) Alternative methods for limit expression. The department may use an alternative method from the methodology specified in subs. (3) to (5) to express water quality-based effluent limitations in permits if the department determines that the methods in subs. (3) to (5) are impracticable and an alternative methodology is necessary and appropriate and adequately protective of the designated uses of the receiving and downstream waters as specified in ch. NR 102.

NR 106.07 History History: Cr. Register, February, 1989, No. 398, eff. 3-1-89; renum. (2) to (5) to be (3) to (6) and am., cr. (2), (6) (d) to (f) and (7) to (9), Register, August, 1997, No. 500, eff. 9-1-97; correction in (7) made under s. 13.93 (2m) (b) 1., Stats., Register, October, 1999, No. 526; correction in (8) made under s. 13.93 (2m) (b) 7., Stats., Register February 2004 No. 578; CR 09-123: am. (2) (intro.), (a) and (b) Register July 2010 No. 655, eff. 8-1-10; CR 15-085: cr. (1) (title), r. and recr. (2) to (5), cr. (5m), (6) (title), (7) (title), (8) (title), am. (8), cr. (9) (title), (10) Register August 2016 No. 728, eff. 9-1-16.

NR 106.08 NR 106.08 Determination of the necessity for whole effluent toxicity testing requirements and limitations.

NR 106.08(1) (1) General. The department shall establish whole effluent toxicity testing requirements and limitations whenever necessary to meet applicable water quality standards as specified in chs. NR 102 to 105 as measured by exposure of aquatic organisms to an effluent and specified effluent dilutions. When considering the necessity for whole effluent toxicity testing requirements and limitations, the department shall consider in-stream biosurvey data and data from ambient toxicity analyses, whenever such data are available.

NR 106.08(2) (2) Determination of necessity. If representative discharge data are available for an effluent being discharged from a point source, whole effluent toxicity testing requirements are necessary when any of the following apply:

NR 106.08(2)(a) (a) Existing aquatic life toxicity test data generated according to standard test protocols indicate a potential for an effluent from a point source discharge to adversely impact the receiving water aquatic life community.

NR 106.08(2)(b) (b) A water quality-based effluent limitation for a toxic substance is determined necessary in s. NR 106.05.

NR 106.08(3) (3) Representative data. Toxicity test data available to the department shall be considered representative when all of those data meet the following conditions:

NR 106.08(3)(a) (a) Data are representative of normal discharge conditions and current effluent quality.