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)(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:
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) When the provisions of this section cannot be invoked because representative discharge data are not available for a substance, water quality based effluent limitations may be established if, in the judgment of the department, water quality standards will be exceeded if the discharge from the point source is not limited. If, in the judgment of the department, the discharge from a point source may exceed the water quality standards, but the collection of representative discharge data is not possible due to the inability of the most sensitive approved method to quantify discharge levels and, in the judgment of the department the application numeric effluent limitations in a permit is infeasible or impractical, then the permittee may request an alternative to a numerical effluent limitation. The alternative shall consist of a permit requirement to conduct a cost-effective pollutant minimization program as specified in
s. NR 106.04 (5). Approved methods are those specified in
ch. NR 219 or
40 CFR part 136.
NR 106.05 Note
Note: A department guidance document finalized in May 1996, entitled "Wisconsin Strategy for Regulating Mercury in Wastewater", describes how the department evaluates whether an effluent limitation or a pollutant minimization program for mercury is appropriate.
NR 106.05(9)
(9) Regardless of the results of the analysis conducted under this section, the department may, whenever determined necessary, require monitoring for any toxic or organoleptic substance.
NR 106.05 History
History: Cr.
Register, February, 1989, No. 398, eff. 3-1-89; renum. (1) to be (1) (a), cr. (1) (b) and (c), am. (3) (a) to (c), (4) (a) to (c), (5) (b), (6) (a) and (b) and (8),
Register, August, 1997, No. 500, eff. 9-1-97;
CR 03-050: am. (5) (a)
Register February 2004 No. 578, eff. 3-1-04;
CR 09-123: am. (5) (a)
Register July 2010 No. 655, eff. 8-1-10.
NR 106.06
NR 106.06
Calculation of water quality based effluent limitations for toxic and organoleptic substances. NR 106.06(1)(a)(a) The department shall establish water quality based effluent limitations for point source dischargers whenever such limitations are necessary, as determined by any method in this section, to meet the applicable water quality standards, criteria and secondary values as determined in
chs. NR 102 to
105.
NR 106.06(1)(b)1.1. Water quality based effluent limitations for toxic and organoleptic substances shall be determined to attain and maintain water quality standards and criteria or secondary values, specified in or determined according to procedures in
ch. NR 105, at the point of discharge. Effluent limitations shall be established to protect downstream waters whenever the department has information to make the determinations.
NR 106.06(1)(b)2.
2. For discharges to Green Bay that are north of 44° 32' 30" north latitude, the cold water community criteria shall apply in effluent limit calculations. For discharges to Green Bay that are south of 44° 32' 30" north latitude, effluent limitations shall be established in accordance with
subd. 1.
NR 106.06(2)
(2) Limitations for bioaccumulative chemicals of concern (bccs). NR 106.06(2)(a)(a) Notwithstanding any other provisions in
chs. NR 102 and
106, beginning on March 23, 1997, effluent limitations for new or expanded discharges of BCCs into waters of the Great Lakes system as defined in
s. NR 102.12 may not exceed the most stringent applicable water quality criteria or secondary values for BCCs. Effluent limitations for expanded discharges of BCCs with permit limitations shall be determined by means of a mass balance where the limitation for the existing portion of a permitted discharge shall be determined using the requirements of
sub. (4) and the limitation for the expanded portion of the discharge may not exceed the most stringent criteria or value for that BCC.
NR 106.06(2)(b)
(b) For the purposes of
par. (a), "expanded discharge" means any change in concentration, level or loading of a substance which would exceed a limitation specified in a current WPDES permit, or which, according to the procedures in
s. NR 106.05 would result in the establishment of a new limitation in a reissued or modified WPDES permit. "New discharge" means any point source which has not received a WPDES permit from the department prior to September 1, 1997.
NR 106.06 Note
Note: The Great Lakes Water Quality Initiative requires that for existing discharges of BCCs in waters of the Great Lakes system, effluent limitations may not exceed the most stringent criteria or secondary value beginning March 23, 2007, with two exceptions. Prior to that date, DNR will develop additional rules to implement this requirement for existing discharges.
NR 106.06(2)(c)
(c) Effluent limitations for discharges of BCCs into waters of the Great Lakes system as defined in
s. NR 102.12 that are based on human health criteria or secondary values calculated according to procedures in
ch. NR 105, shall be also based on the most protective designated use: cold water, public water supply.
NR 106.06(3)(a)(a) The department shall establish water quality based effluent limitations to ensure that substances are not present in amounts which are acutely harmful to animals, plants or aquatic life in all surface waters including those portions of the mixing zone normally habitable by aquatic life and effluent channels as required by
s. NR 102.04 (1).
NR 106.06(3)(b)
(b) To assure compliance with
par. (a) and except as provided in
par. (c), water quality based effluent limitations shall equal the final acute value as determined in
s. NR 105.05 or the secondary acute value as determined in
s. NR 105.05 (4) for the respective fish and aquatic life subcategory for which the receiving water is classified. Effluent limitations for substances for which criteria may be expressed as dissolved concentrations may be established according to
sub. (7).
NR 106.06(3)(c)
(c) Except as provided in
par. (d), water quality based effluent limitations may exceed the final acute value or the secondary acute value within a zone of initial dilution provided that the acute toxicity criteria or secondary acute values are met within a short distance from the point of discharge. A zone of initial dilution shall only be provided if the discharger demonstrates to the department that mixing of the effluent with the receiving water in the zone of initial dilution is rapid and all the following conditions are met:
NR 106.06(3)(c)2.
2. The discharge does not constitute a significant portion of the streamflow or otherwise dominate the receiving water.
NR 106.06(3)(c)3.
3. The discharge velocity is not less than 3 meters per second (10 feet per second) unless an alternative discharge velocity, which similarly minimizes organism exposure time, is determined appropriate for the specific site.
NR 106.06(3)(c)4.
4. The acute toxicity criteria or secondary acute values must be met within 10% of the distance from the edge of the outfall structure to the edge of a mixing zone which may be determined in accordance with
s. NR 102.05 (3).
NR 106.06(3)(c)5.
5. The acute toxicity criteria or secondary acute values shall be met within a distance of 50 times the discharge length scale in any direction. The discharge length scale is defined as the square root of the cross-sectional area of any discharge outlet. If a multiport diffuser is used, this requirement must be met for each port using the appropriate discharge length scale for that port.
NR 106.06(3)(c)6.
6. The acute toxicity criteria or secondary acute values shall be met within a distance of 5 times the local water depth in any horizontal direction from any discharge outlet. The local water depth is defined as the natural water depth (existing prior to the installation of the discharge outlet) prevailing under the mixing zone design conditions for the site.
NR 106.06(3)(d)
(d) For toxic substances with water quality criteria related to one or more other water quality parameters, effluent limitations shall be calculated using the effluent value for the water quality parameter. Water quality parameters include, but are not limited to, pH, temperature and hardness.
NR 106.06(4)
(4) Limitations based on chronic toxicity or long-term impacts. NR 106.06(4)(a)(a) Water quality criteria and secondary values. The department shall calculate water quality based effluent limitations to ensure that the chronic toxicity criteria (CTC), the wildlife criteria (WC), the taste and odor criteria (TOC), the human threshold criteria (HTC), and human cancer criteria (HCC) appropriate for the receiving water as specified in
chs. NR 102 to
105 and the secondary chronic values determined according to
ch. NR 105 will be met after dilution with an appropriate allowable quantity of receiving water flow as specified in this subsection,
subs. (5) to
(11) and
s. NR 106.11. The available dilution shall be determined according to
par. (c) unless the conditions specified in
s. NR 102.05 (3) or
sub. (2) require less dilution or no dilution be allowed. Effluent limitations for substances for which criteria may be expressed as dissolved concentrations may be established according to
sub. (7).
NR 106.06(4)(b)
(b)
Calculation of limits. Water quality based effluent limitations to meet the requirements of this subsection shall be calculated using the procedure specified in
subd. 1. or
2., except as provided in
sub. (2) or
(6).
NR 106.06(4)(b)1.
1. For discharges of toxic or organoleptic substances to flowing receiving waters, the water quality based effluent limitation for a substance shall be calculated using the following conservation of mass equation whenever the background concentration is less than the water quality criterion or secondary value:
NR 106.06 Note
Note: In applying this equation, all units for the flow and concentration parameters respectively, shall be consistent.
NR 106.06(4)(b)2.
2. For discharges of toxic or organoleptic substances to receiving waters which do not exhibit a unidirectional flow at the point of discharge, such as lakes or impoundments, the department may calculate, in the absence of specific data, water quality based effluent limitations using the following equation whenever the background concentration is less than the water quality criterion or secondary value:
On a case-by-case basis other dilutional factors may be used, but in no case may the dilution allowed exceed an area greater than the area where discharge induced mixing occurs. The discharge is also subject to the conditions specified in
s. NR 102.05 (3). The discharger may be required to determine the size of the mixing zone using acceptable models or dye studies.
NR 106.06(4)(b)3.
3. The limitation calculated in
subd. 1. or
2. may be converted to a maximum load limitation by multiplying the calculated concentration limitation by the rate of effluent flow as determined in
par. (d) and appropriate conversion factors.
NR 106.06(4)(c)
(c) Receiving water design flow (Qs). The value of Qs to be used in calculating the effluent limitation for discharges to flowing waters shall be determined as follows:
NR 106.06(4)(c)1.
1. The department shall make reasonable efforts to determine the area of the zone of passage and the dilution characteristics of discharges.
NR 106.06(4)(c)2.
2. The department may require that the discharger provide information on the discharge mixing and dilution characteristics of discharges.
NR 106.06(4)(c)3.
3. The discharger shall be allowed to demonstrate, through appropriate and reasonable methods that an adequate zone of free passage exists in the cross-section of the receiving water or that dilution is accomplished rapidly such that the extent of the mixing zone is minimized. In complex situations, the department may require that the demonstration under this subdivision include water quality modeling or field dispersion studies.
NR 106.06(4)(c)4.
4. Following the determinations under
subds. 1. to
3., the value of Qs of the receiving water for calculating effluent limitations based upon the chronic toxicity criteria specified in
s. NR 105.06 or secondary chronic values shall be determined on a case-by-case basis. In no case may Qs exceed the larger of the average minimum 7-day flow which occurs once in 10 years (7-day Q10) or, if sufficient information is available to calculate a biologically based receiving water design flow, the flow which prevents an excursion from the criterion or secondary value using a duration of 4 days and a frequency of less than once every 3 years (4-day, 3-year biological flow).
NR 106.06(4)(c)5.
5. If the requirements of
subds. 2. and
3. are not satisfied, the department shall notify the permittee and identify the deficiencies and allow additional time, if necessary, to complete the demonstration. If the demonstration cannot be completed satisfactorily, the value of Qs of the receiving water for calculating effluent limitations based upon the chronic toxicity criteria specified in
s. NR 105.06 or secondary chronic values shall equal 1/4 of the 7-day Q10 or 1/4 of the 4-day, 3 year biological flow. In no case may the value of Qs, of the receiving water, for calculating effluent limitations based upon the chronic toxicity criteria or secondary chronic values developed according to
ch. NR 105, exceed 1/4 of the 7-day Q10 or 1/4 of the 4-day, 3-year biological flow if the department determines that the discharge has a potential to jeopardize the continued existence of any endangered or threatened species listed under
ch. NR 27 and conforming to section 7 of the endangered species act,
16 USC 1536.
NR 106.06(4)(c)6.
6. Qs may be reduced from those values calculated in
subds. 3. to
5. where natural receiving water flow is significantly altered by flow regulation.
NR 106.06(4)(c)7.
7. Following the determinations under
subds. 1. to
3., the value of Qs of the receiving water for calculating effluent limitations based upon the wildlife criteria or secondary values developed according to
ch. NR 105 shall be determined on a case-by-case basis. In no case may the Qs exceed the average minimum 90-day flow which occurs once in 10 years (90-day Q10) or if the 90-day Q10 flow is not available, the average minimum 30-day flow which occurs once in 5 years (30-day Q5) or 85% of the average minimum 7-day flow which occurs once in 2 years (7-day Q2).
NR 106.06(4)(c)8.
8. If the requirements of
subds. 2. and
3. are not satisfied, the department shall notify the permittee and identify the deficiencies and allow additional time, if necessary, to complete the demonstration. Except as provided in
subd. 12., if the demonstration cannot be completed satisfactorily, the value of Qs of the receiving water for calculating effluent limitations based upon the wildlife criteria specified in
s. NR 105.07 shall equal ¼ of the 90-day Q10 or ¼ of the 30-day Q5 or ¼
of 85% of the 7-day Q2. In no case may the value of Q5 of the receiving water, for calculating effluent limitations based upon the wildlife criteria or secondary values developed according to
ch. NR 105, exceed ¼ of the 90-day Q10 or ¼ of the 30-day Q5 or ¼
of 85% of the 7-day Q2 if the department determines that the discharge has a potential to jeopardize the continued existence of any endangered or threatened species listed under
ch. NR 27 and conforming to section 7 of the endangered species act,
16 USC 1536.
NR 106.06(4)(c)9.
9. Except as provided in
subd. 12., following the determinations under
subds. 1. to
3., the value of Qs of the receiving water for calculating effluent limitations based upon the human cancer criteria, human threshold criteria or secondary values developed according to
ch. NR 105 shall be determined on a case-by-case basis. In no case may Qs exceed the harmonic mean flow.
NR 106.06(4)(c)10.
10. If the requirements of
subds. 2. and
3. are not satisfied, the department shall notify the permittee and identify the deficiencies and allow additional time, if necessary, to complete the demonstration. Subject to
subd. 12., if the demonstration cannot be completed satisfactorily, the value of Qs of the receiving water for calculating effluent limitations based upon the human cancer criteria or secondary values or the human threshold criteria or secondary values specified in
ch. NR 105 shall equal ¼ of the harmonic mean flow.
NR 106.06(4)(c)11.
11. Except as provided in
subd. 12., the value of Qs shall equal the mean annual flow of the receiving water for calculating effluent limitations based upon the taste and odor criteria as specified in
ch. NR 102.
NR 106.06(4)(c)12.
12. Qs may be reduced from those values calculated in
subds. 9.,
10., and
11.,whenever the department determines such discharges may directly affect public drinking water supplies.
NR 106.06(4)(d)1.1. For dischargers subject to
ch. NR 210 and
which discharge for 24 hours per day on a year-round basis, Qe shall equal the maximum effluent flow, expressed as a daily average, that is anticipated to occur for 12 continuous months during the design life of the treatment facility unless it is demonstrated to the department that such a design flow rate is not representative of projected flows at the facility.
NR 106.06(4)(d)2.
2. For all other dischargers not subject to
ch. NR 210, Qe shall equal either
subd. 2. a. or
b. for effluent limitations based on aquatic life chronic criteria or chronic secondary values, and shall equal either
subd. 2. a. or
c. for effluent limitations based on wildlife, human threshold, human cancer or taste and odor criteria or secondary values. Whenever calculating Qe, the department may consider a projected increase in effluent flow that will occur when production is increased or modified, or another wastewater source, including stormwater, is added to an existing wastewater treatment facility. This subdivision does not waive the requirements of
ch. NR 207.
NR 106.06(4)(d)2.a.
a. The maximum effluent flow, expressed as a daily average, that has occurred for 12 continuous months and represents normal operations; or
NR 106.06(4)(d)2.b.
b. The maximum effluent flow, expressed as a daily average, that has occurred for 7 continuous days and represents normal operations; or
NR 106.06(4)(d)2.c.
c. The maximum effluent flow, expressed as a daily average, that has occurred for 30 continuous days and represents normal operations.
NR 106.06(4)(d)3.
3. For seasonal discharges, discharges proportional to stream flow, or other unusual discharge situations, Qe shall be determined on a case by case basis.
NR 106.06(4)(e)
(e)
Background concentrations of toxic or organoleptic substances (Cs). The representative background concentration of a toxic or organoleptic substance shall be used in deriving chemical specific water quality based effluent limitations. Except as provided elsewhere in this paragraph, the representative background concentration shall equal the geometric mean of the acceptable available data for a substance. Background concentrations may not be measured at a location within the direct influence of a point source discharge.
NR 106.06(4)(e)1.
1. The department shall determine representative background concentrations of toxic substances on a case-by-case basis using available data on the receiving water or similar waterbodies in the state, including acceptable and available caged or resident fish tissue data, available or projected pollutant loading data, and best professional judgment.
NR 106.06(4)(e)2.
2. The department may utilize representative seasonal concentrations and may consider other information on background concentrations submitted to the department.
NR 106.06(4)(e)3.
3. When evaluating background concentration data, commonly accepted statistical techniques shall be used to evaluate data sets consisting of values both above and below the level of detection. When all of the acceptable available data in a data set category, such as water column, caged or resident fish tissue, are below the level of detection for a pollutant, then all the data for that pollutant in that data set shall be assumed to be zero.
NR 106.06(5)
(5) Values for parameters which affect the limit. For toxic substances with water quality criteria related to one or more other water quality parameters, the department may calculate effluent limitations in consideration of those other water quality parameters. Water quality parameters include but are not limited to pH, temperature and hardness. The department shall determine the value of the water quality parameters on a case-by-case basis as follows:
NR 106.06(5)(a)1.1. The geometric mean of available data for the receiving water shall be used, except the arithmetic mean for pH shall be used.
