Chapter NR 106

NR 106.92   Authority of a publicly owned treatment works to regulate chloride discharges.

NR 106.93   New discharges.

NR 106.94   Relocation of an existing discharge.

NR 106.95   Multiple discharges.

NR 106.96   Analytical methods and laboratory requirements.

Subchapter VIII — Permit Requirements for PFOS and PFOA Discharges

NR 106.97   Purpose.

NR 106.975   Definitions.

NR 106.98   Determination of the necessity for reducing PFOS and PFOA in discharges.

NR 106.985   PFOS and PFOA minimization plans, permit implementation procedures schedule.

NR 106.99   PFOS and PFOA minimization plans.

NR 106.995   Sampling and laboratory analysis requirements.

NR 106.996   New dischargers or new sources.

Ch. NR 106 Note Note: Corrections made under s. 13.93 (2m) (b) 7., Stats., Register, August, 1997, No. 500.

subch. I of ch. NR 106 Subchapter I — Applicability

NR 106.01 NR 106.01 Purpose. One purpose of this chapter is to specify how the department will calculate water quality based effluent limitations under s. 283.13 (5), Stats., for toxic and organoleptic substances and whole effluent toxicity. The other purpose of this chapter is to specify how the department will decide if and how these limitations will be included in Wisconsin pollution discharge elimination system (WPDES) permits. Water quality based effluent limitations for toxic and organoleptic substances are needed to assure attainment and maintenance of surface water quality standards as established in accordance with s. 281.15 (1), Stats., and as set forth in chs. NR 102 to 105.

NR 106.01 History History: Cr. Register, February, 1989, No. 398, eff. 3-1-89; correction made under s. 13.93 (2m) (b) 7., Stats., Register October 2002 No. 562.

NR 106.02 NR 106.02 Applicability. The provisions of this chapter are applicable to point sources which discharge wastewater containing toxic or organoleptic substances to surface waters of the state.

NR 106.02 History History: Cr. Register, February, 1989, No. 398, eff. 3-1-89.

NR 106.03 NR 106.03 Definitions. The following definitions are applicable to terms used in this chapter.

NR 106.03(1g) (1g) “AMZ” means acute mixing zone concentration based on presence of a zone of initial dilution under s. NR 106.06 (3) (c).

NR 106.03(1r) (1r) “Bioaccumulative chemical of concern” or “BCC” means any substance that has the potential to cause adverse effects which, upon entering the surface waters, accumulates in aquatic organisms by a human health or wildlife bioaccumulation factor greater than 1000.

NR 106.03(2) (2) “Biologically based design flow” means a receiving water design flow to protect fish and aquatic life for which both the duration of exposure is expressed in days and the allowable frequency of excursion is expressed in years. An example of a biologically based design flow is a 4-day 3-year design flow which corresponds to the lowest 4-day average flow that will limit excursions from any water quality criteria or secondary values to no more than once in 3 years.

NR 106.03(2m) (2m) “Deficiency toxicity” means a condition that exists when adverse effects occur to aquatic organisms because concentrations of common ions are too low.

NR 106.03 Note Note: Changes in the concentration of ions in surrounding waters can cause organisms to expend too much energy trying to regulate the balance of water and dissolved materials in bodily fluids, and may result in death.

NR 106.03 Note Note: Examples of common ions are sodium, calcium, magnesium, potassium, etc.

NR 106.03(3) (3) “Dynamic models” means computer simulation models which use real or derived time series data to predict a time series of observed or derived receiving water concentrations. Methods include continuous simulation, Monte Carlo simulations, or other similar statistical or deterministic techniques.

NR 106.03(4) (4) “EC50” means the point estimate of the concentration of a toxic substance, wastewater effluent or other aqueous mixture which causes an adverse effect including mortality to 50% of the exposed organisms in a given time period, when compared to an appropriate control.

NR 106.03(4g) (4g) “Great Lakes” means the open Wisconsin waters of Lake Superior, Lake Michigan, Green Bay, and Chequamegon Bay, as well as adjoining open waters that exhibit characteristics of Lake Superior, Lake Michigan, Green Bay, and Chequamegon Bay, or in other ways are determined by the department to be equivalent to these waters.

NR 106.03(4r) (4r) “Great Lakes system” means all the surface waters within the drainage basin of the Great Lakes.

NR 106.03(5) (5) “IC25” means the point estimate of the concentration of a toxic substance, wastewater effluent or other aqueous mixture that would cause a 25% reduction in a nonlethal biological measurement, such as reproduction or growth, of the exposed test organisms in a given time period.

NR 106.03(5m) (5m) “IC50” means the point estimate of the concentration of a toxic substance, wastewater effluent or other aqueous mixture that would cause a 50% reduction in a nonlethal biological measurement, such as reproduction or growth, of the exposed test organisms in a given time period.

NR 106.03(6) (6) “IWC” or “Instream waste concentration” means an estimate of the proportion of effluent to total volume of water (receiving water + effluent). The IWC is calculated according to the following equation:

where:

Qe = effluent flow

f = fraction of the Qe withdrawn from the receiving water

Qs = receiving water flow (in most cases ¼ of a low flow value, such as the Q7,10, is used in order to allow a free zone of passage for aquatic organisms).

NR 106.03(7) (7) “LC50” means the point estimate of the concentration of a toxic substance, wastewater effluent or other aqueous mixture which is lethal to 50% of the exposed organisms in a given time period, when compared to an appropriate control.

NR 106.03(8) (8) “Limit of detection” or “LOD” means the lowest concentration level that can be determined to be significantly different from a blank for that analytical test method and sample matrix.

NR 106.03(9) (9) “Limit of quantitation” or “LOQ” means the concentration of an analyte at which one can state with a degree of confidence for that analytical test method and sample matrix that an analyte is present at a specific concentration on the sample tested.

NR 106.03(11m) (11m) “Same waterbody” means hydrologically connected waters of the State with similar water quality characteristics in which a pollutant can travel between in a reasonable period of time without significantly changing chemically or physically. Hydrological connections can include surface and groundwater connections.

NR 106.03(12) (12) “Toxicity test” means a test which determines the toxicity of a chemical substance, wastewater effluent or other aqueous mixture using living organisms. A toxicity test measures the degree of response of exposed test organisms to a chemical substance, wastewater effluent or other aqueous mixture.

NR 106.03(13) (13) “TUa” or “toxic unit acute” means a value that is equal to 100 divided by the LC50 except as provided in s. NR 106.08 (6) (d).

NR 106.03(13m) (13m) “TUc” or “toxic unit chronic” means a value that is equal to 100 divided by the IC25 or the IC50 except as provided in s. NR 106.08 (6) (d).

NR 106.03(14) (14) “Whole effluent toxicity” or “WET” means the aggregate toxic effect of an effluent as measured directly by a toxicity test.

NR 106.03 History History: Cr. Register, February, 1989, No. 398, eff. 3-1-89; r. (7), renum. (1) to (6), (8) and (9) to be (4), (7) to (9), (12) and (14) and am. (2), (4), (7) and (12), cr. (1), (5), (6), (10), (11) and (13), Register, August, 1997, No. 500, eff. 9-1-97; CR 09-123: r. and recr. (6) Register July 2010 No. 655, eff. 8-1-10; CR 15-084: cr. (4g), (4r), (11m) Register August 2016 No. 728, eff. 9-1-16; CR 15-085: renum. (1) to (1r), cr. (1g), (2m), (5m), r. (10), (11), am. (13), cr. (13m), am. (14) Register August 2016 No. 728, eff. 9-1-16.

subch. II of ch. NR 106 Subchapter II — General Procedures for Effluent Limitations

NR 106.04 NR 106.04 General.

NR 106.04(1) (1) The department shall establish water quality-based effluent limitations whenever categorical effluent limits required under s. 283.13, Stats., are less stringent than necessary to achieve applicable water quality standards specified in chs. NR 102 to 105. Water quality-based effluent limitations for a point source shall be specified in the permit for that point source.

NR 106.04(2) (2) In no case may the water quality based effluent limitations be less stringent than applicable categorical effluent limitations.

NR 106.04(3) (3) The department shall establish limitations for toxic and organoleptic substances if any of the conditions specified in s. NR 106.05 are met. Limitations shall be established according to the methods provided in s. NR 106.06 and included in WPDES permits according to the conditions provided in s. NR 106.07. The department shall establish limitations for whole effluent toxicity if any of the conditions specified in s. NR 106.08 are met. Whole effluent limitations shall be established and included in WPDES permits according to the methods provided in ss. NR 106.08 and 106.09.

NR 106.04(3m) (3m) In lieu of imposing limitations at the point of discharge when imposition of limitations at the point source discharge location is impracticable or infeasible, the department may impose water quality-based effluent limitations on an internal waste stream before that waste stream mixes with other waste streams or cooling water streams. Monitoring requirements as specified in s. NR 106.07 (1) shall also be applied to the internal waste streams in these instances.

NR 106.04(4) (4) Water quality based effluent limitations or monitoring requirements for toxic or organoleptic substances or whole effluent toxicity may be removed from a permit, subject to public notice and opportunity for hearing under ch. NR 203, if the limitation is determined to be unnecessary based on the procedures presented in this chapter or based on other information available to the department.

NR 106.04(5) (5) For purposes of this chapter, a cost-effective pollutant minimization program is an activity which has as its goal the reduction of all potential sources of the pollutant for the purpose of maintaining the effluent at or below the water quality based effluent limitation. The pollutant minimization programs specified in ss. NR 106.05 (8), 106.06 (6) (d), 106.07 (6) (f) and 106.145 (7) shall include investigation of treatment technologies and efficiencies, process changes, wastewater reuse or other pollution prevention techniques that are appropriate for that facility, taking account of the permittee’s overall treatment strategies, facilities plans and operational circumstances. Past documented pollution prevention or treatment efforts may be used to satisfy all or part of a pollution minimization program requirement. The permittee shall submit to the department an annual status report on the progress of a pollutant minimization program.

NR 106.04 History History: Cr. Register, February, 1989, No. 398, eff. 3-1-89; am. (3), cr. (5), Register, August, 1997, No. 500, eff. 9-1-97; CR 02-019: am. (5) Register October 2002 No. 562, eff. 11-1-02; CR 15-085: am. (1) (intro.), cr. (3m) Register August 2016 No. 728, eff. 9-1-16.

NR 106.05 NR 106.05 Determination of the necessity for water quality based effluent limitations for toxic and organoleptic substances.

NR 106.05(1) (1) 

NR 106.05(1)(a) (a) General. The department shall establish water quality based effluent limitations for point source dischargers whenever the discharges from those point sources contain(s) toxic or organoleptic substances at concentrations or loadings which do not, as determined by any method in this section, meet applicable water quality standards specified in chs. NR 102 to 105.

NR 106.05(1)(b) (b) Determining necessity for limitations based on secondary values. The department may establish water quality based effluent limitations for point source discharges based on secondary values calculated according to ch. NR 105. The department shall calculate secondary values and establish limitations for toxic and organoleptic substances in permits based on secondary values when, in the judgment of the department, one or more of the following factors support the necessity for the values, in conjunction with the procedures in subs. (2) to (8).

NR 106.05(1)(b)1. 1. Whole effluent toxicity or other biomonitoring or bioassay test results indicate toxicity to test or other species.

NR 106.05(1)(b)2. 2. The use designation of the receiving water is or may be impaired.

NR 106.05(1)(b)3. 3. There is other information that the industrial category or subcategory of the point source or the industrial or other sources discharging to a publicly owned treatment works discharges the substance.

NR 106.05(1)(b)4. 4. The substance in the wastewater will not be adequately removed or reduced by the type of wastewater treatment provided.

NR 106.05(1)(b)5. 5. The ecological or environmental risk from the substance may be significant when discharged to surface waters.

NR 106.05(1)(b)6. 6. Other relevant factors which may cause an adverse effect on surface waters as specified in s. NR 105.04 (1).

NR 106.05(1)(c) (c) If the department determines that a limitation based on an aquatic life acute or chronic secondary value should be established in a permit according to the provisions in this section, a permittee may request an alternative WET limit in accordance with s. NR 106.07 (7).

NR 106.05 Note Note: A toxic or organoleptic substance includes, but is not limited to, those substances in Table 6 of 40 CFR part 132.

NR 106.05(2) (2) When considering the necessity for water quality based effluent limitations, the department shall consider in-stream biosurvey data and data from ambient toxicity analyses whenever such data are available.

NR 106.05(3) (3) If representative discharge data are available for a toxic or organoleptic substance being discharged from a point source, limitations shall be established in accordance with any one of the following conditions:

NR 106.05(3)(a) (a) The discharge concentration of the substance for any day exceeds the limit of detection and exceeds the limitations based on either the acute toxicity criterion or secondary acute value for the substance as determined in s. NR 106.06 (3) where appropriate,

NR 106.05(3)(b) (b) The arithmetic average discharge concentration of the substance for any 4 consecutive days calculated as described in sub. (7) exceeds the limit of detection and exceeds the limitations based on either the chronic toxicity criterion or secondary chronic value for the substance as determined in s. NR 106.06 (4).

NR 106.05(3)(c) (c) The arithmetic average discharge concentration of the substance for any 30 consecutive days calculated as described in sub. (7) exceeds the limit of detection and exceeds any limitation based on the wildlife, human threshold, or human cancer criteria or secondary values, or taste and odor criteria for the substance as determined in s. NR 106.06 (4).

NR 106.05(4) (4) If at least 11 daily discharge concentrations of the substance are greater than the limit of detection and the requirements of sub. (3) do not result in the need for an effluent limitation, water quality based effluent limitations are necessary for a substance in a point source discharge if the upper 99th percentile of available discharge concentrations as calculated in sub. (5) meets any of the conditions specified in pars. (a) to (c).

NR 106.05(4)(a) (a) The upper 99th percentile of daily discharge concentrations of the substance exceeds the limitation based on either the acute toxicity criterion or the secondary acute value for the substance as determined in s. NR 106.06 (3).

NR 106.05(4)(b) (b) The upper 99th percentile of 4-day average discharge concentration of the substance exceeds the limitation based on either the chronic toxicity criterion or the secondary chronic value for the substance as determined in s. NR 106.06 (4), or

NR 106.05(4)(c) (c) The upper 99th percentile of 30-day average discharge concentration of the substance exceeds any limitation based on the wildlife, human threshold, or human cancer criteria or secondary value, or taste and odor criteria for the substance as determined in s. NR 106.06 (4).

NR 106.05(5) (5) This subsection shall be used to calculate upper 99th percentile values unless a probability distribution other than log normal is determined to be more appropriate and alternate methods to calculate the upper 99th percentile are available.

NR 106.05(5)(a) (a) When available daily discharge concentrations of the substance are not serially correlated and at least 11 concentrations are greater than the limit of detection, the upper 99th percentile of the daily average, the 4-day average and the 30-day average discharge concentrations may be calculated as follows:

P99= exp (mudn + Zpsigmadn)

NR 106.05(5)(b) (b) When the daily discharge concentrations of any substance are serially correlated, the serially correlated data may be adjusted using appropriate methods such as that presented in Appendix E of “Technical Support Document for Water Quality-based Toxics Control”, U.S. environmental protection agency, March 1991 (EPA/505/2-90-001). The equation presented in par. (a) may be used after adjustment of the serially correlated data.

NR 106.05(6) (6) If less than 11 daily discharge concentrations of the substance are greater than the limit of detection, and the requirements in sub. (3) do not result in an effluent limitation, water quality based effluent limitations are necessary for a substance in a point source discharge if the arithmetic average of available discharge concentrations as calculated in sub. (7) exceeds any value determined in par. (a) or (b):

NR 106.05(6)(a) (a) One fifth of the limitation based on the acute toxicity criterion or secondary acute value for the substance, as determined in s. NR 106.06 (3) where appropriate, or

NR 106.05(6)(b) (b) One fifth of any limitation based on chronic toxicity criteria or secondary chronic values or long-term impacts as determined in s. NR 106.06 (4).

NR 106.05(7) (7) The arithmetic average discharge concentration as used in subs. (3) and (6) shall be calculated using all available discharge data treated according to this subsection.

NR 106.05(7)(a) (a) If, in the judgment of the department, the analytical methods used to test for the substance represent acceptable methods, all values reported as less than the limit of detection shall be set equal to zero for calculation of the average concentration.

NR 106.05(7)(b) (b) If, in the judgment of the department, the analytical methods used to test for the substance do not represent the best acceptable methods, all values reported as less than the limit of detection shall be discarded from the data.

NR 106.05(8) (8) If representative discharge data are not available for a substance, the department may include water quality-based effluent limitations in a permit if, in the judgment of the department, water quality standards will be exceeded if the discharge of the substance is not limited.