Chapter NR 106

NR 106.82(4) (4) “Daily maximum interim limitation” means an effluent limitation calculated by the department which may be either:

NR 106.82(4)(a) (a) The upper 99th percentile of the permittee’s representative data available to the department, or

NR 106.82(4)(b) (b) A value no greater than 105% of the permittee’s highest representative effluent datum.

NR 106.82(5) (5) “Reasonably meet” means that all of the permittee’s representative effluent data would, using appropriate statistical techniques, be expected to be less than or equal to the target limitation following the completion of all of the source reduction efforts required by the permit.

NR 106.82(6) (6) “Representative effluent data” means data, above the level of detection, which is not serially correlated and which represents normally expected effluent concentrations of chloride, collected during a period that can represent current or expected operations, or both, within the term of the permit.

NR 106.82(7) (7) “Target limitation” means an effluent limitation which the permittee can reasonably meet within the term of the permit, following implementation of appropriate voluntary source reduction activities.

NR 106.82(8) (8) “Target value” means an effluent concentration of chlorides which a permittee may be expected to reasonably meet following implementation of appropriate voluntary source reduction activities. A target value is not an enforceable limitation under the terms of the permit program, but establishes a measure of progress of source reduction activities.

NR 106.82(9) (9) “Weekly average interim limitation” means an effluent limitation calculated by the department which may be either:

NR 106.82(9)(a) (a) The upper 99th percentile of the permittee’s 4-day average of the representative data available to the department, or

NR 106.82(9)(b) (b) A value no greater than 105% of the permittee’s calculated highest weekly average of the representative effluent data.

NR 106.82(10) (10) “WPDES” means Wisconsin pollutant discharge elimination system.

NR 106.82 History History: Cr. Register, January, 2000, No. 529, eff. 2-1-00.

NR 106.83 NR 106.83 Regulation of chloride discharges.

NR 106.83(1) (1) Chloride effluent limitations. The department shall evaluate the need to establish effluent limitations for chloride whenever representative effluent data indicate that the discharge from a point source contains chloride. If the department determines that a water quality-based effluent limitation for chloride is needed, a calculated limitation as defined in s. NR 106.82 (1) shall be included in the permit to meet the applicable water quality standards specified in chs. NR 102 to 105, unless a chloride variance is given pursuant to sub. (2).

NR 106.83(2) (2) Chloride variance.

NR 106.83(2)(a) (a) Findings. On February 1, 2000, the department finds that:

NR 106.83(2)(a)1. 1. End-of-pipe wastewater treatment technology for chloride is prohibitively expensive;

NR 106.83(2)(a)2. 2. End-of-pipe wastewater treatment technology for chloride produces a concentrated brine that can be as much or more of an environmental liability than the untreated effluent;

NR 106.83(2)(a)3. 3. Appropriate chloride source reduction activities are preferable environmentally to end-of-pipe effluent treatment in most cases; and

NR 106.83(2)(a)4. 4. For some dischargers, attaining the applicable water quality standards specified in chs. NR 102 to 105 may cause substantial and widespread adverse social and economic impacts in the area where the discharger is located.

NR 106.83(2)(a)5. 5. These findings shall be reviewed by the department every 3 years.

NR 106.83(2)(b) (b) Application. An existing discharger seeking a chloride variance under this subsection shall submit an application for a chloride variance when it submits its application for permit reissuance. The application shall include the permittee’s basis for concluding that the findings in sub. (2) (a) for a chloride variance are applicable to its discharge.

NR 106.83(2)(c) (c) Department determinations. The department shall review the application submitted by the permittee. The application shall be approved if the department agrees with the permittee’s basis for concluding that the findings under par. (a) for a chloride variance are applicable to its discharge. The department shall obtain U.S. environmental protection agency approval before a variance is included in a permit under this subsection.

NR 106.83(2)(d) (d) Permit conditions implementing a chloride variance. The department shall grant a chloride variance to an existing discharger when:

NR 106.83(2)(d)1. 1. The findings in par. (a) supporting a chloride variance apply to the specific discharge; and

NR 106.83(2)(d)2. 2. The permittee and the department agree upon specific permit language imposing an interim limitation, a target value or, where appropriate, a target limitation, and source reduction activities.

NR 106.83(3) (3) Interim limitations, target values and target limitations and source reduction activities.

NR 106.83(3)(a) (a) If the permittee and the department agree on the inclusion of voluntary source reduction activities and the imposition of an interim limitation and a target value or a target limitation in its permit, those activities and the interim limitation and target value or target limitations shall become permit requirements.

NR 106.83(3)(b) (b) If the permittee and the department cannot agree on voluntary source reduction activities to be included as permit requirements, those activities may not be included in the permit. If the permittee and the department cannot agree on an interim limitation and target value or a target limitation to be included as permit requirements, those limitations may not be included in the permit.

NR 106.83(3)(c) (c) If the permittee and the department cannot agree on voluntary source reduction activities and both an interim limitation and a target value or an interim limitation and a target limitation to be included as permit requirements, the department shall include a calculated limitation as defined in s. NR 106.82 (1) in the permit to meet the applicable water quality standards specified in chs. NR 102 to 105.

NR 106.83(4) (4) Reapplication for a chloride variance. When a permit containing a chloride variance approved by the department under sub. (2) (c) expires, the permittee may reapply for a chloride variance when it submits its application for permit reissuance. The application shall include the permittee’s basis for concluding that the findings in sub. (2) (a) are applicable to its discharge.

NR 106.83(5) (5) Applicability of the variance process in s. 283.15, stats. If a calculated limitation is included in the permit, a permittee may apply to the department for a variance from the water quality standard used to derive the calculated limitation, pursuant to s. 283.15, Stats. Where a permittee has been granted a chloride variance and its permit includes an interim limitation, a target value, a target limitation and requirements for chloride source reduction activities, the provisions of s. 283.15, Stats., are not applicable to the interim and target limitations.

NR 106.83 History History: Cr. Register, January, 2000, No. 529, eff. 2-1-00; CR 15-085: am. (2) (c) Register August 2016 No. 728, eff. 9-1-16.

NR 106.84 NR 106.84 Compliance with Wisconsin water quality antidegradation rules when reissuing a permit. Chapter NR 207 does not apply in those instances in which a reissued permit includes effluent limitations for chloride which represent a lowering of concentration as compared to the interim limitation in the previous permit.

NR 106.84 History History: Cr. Register, January, 2000, No. 529, eff. 2-1-00.

NR 106.85 NR 106.85 Determination of the necessity for water quality-based effluent limitations.

NR 106.85(1) (1) The department shall determine the need for chloride water quality-based effluent limitations for point source discharges whenever the discharges from the point sources contain chloride at concentrations or loadings which do not, as determined by any method in this section, meet the applicable water quality standards specified in chs. NR 102 to 105.

NR 106.85(2) (2) When considering the necessity for water quality-based effluent limitations, the department shall consider in-stream bio-survey data and data from ambient toxicity analyses whenever the data are available.

NR 106.85(3) (3) When considering the necessity for chloride water quality-based effluent limitations, the department shall compare the upper 99th percentile of available representative discharge concentrations to the calculated limitations, pursuant to s. NR 106.05 (4).

NR 106.85 History History: Cr. Register, January, 2000, No. 529, eff. 2-1-00.

NR 106.86 NR 106.86 Monitoring. Notwithstanding any other section in this subchapter, the department shall determine on a case-by-case basis the chloride monitoring frequency to be required in the permit.

NR 106.86 History History: Cr. Register, January, 2000, No. 529, eff. 2-1-00.

NR 106.87 NR 106.87 Establishment of effluent limitations.

NR 106.87(1) (1) Calculated limitations. If water quality-based effluent limitations for chloride are determined to be necessary, those limitations shall be derived under ss. NR 106.06 and 106.07, and for the purposes of this subchapter, shall be labeled “calculated limitations”.

NR 106.87(2) (2) Interim limitation. The interim limitation may be expressed as both a daily maximum and a weekly average, calculated in accordance with s. NR 106.82 (4) and (9).

NR 106.87(3) (3) Target value. The target value may be expressed as both a daily maximum and a weekly average. The department and the permittee shall consider both the implementation and the anticipated effectiveness of appropriate voluntary source reduction activities in order to determine a target value which is reasonably achievable within the term of the permit.

NR 106.87(4) (4) Target limitation. The target limitation may be expressed as both a daily maximum and a weekly average. The department and the permittee shall consider both the implementation and the anticipated effectiveness of appropriate voluntary source reduction activities in order to determine a target limitation which is reasonably achievable within the term of the permit.

NR 106.87 History History: Cr. Register, January, 2000, No. 529, eff. 2-1-00; CR 15-085: am. (1) Register August 2016 No. 728, eff. 9-1-16.

NR 106.88 NR 106.88 Application of and compliance with chloride effluent limitations in a permit.

NR 106.88(1) (1) Chloride limitations in permits. If chloride water quality-based effluent limitations are deemed to be necessary under s. NR 106.85, the department shall use all of the following procedures to include the calculated limitations in the permit with an appropriate compliance schedule as necessary and appropriate:

NR 106.88(1)(a) (a) Effluent limitations based on an acute criterion shall be expressed in permits as daily maximum limitations, and effluent limitations based on a chronic criterion shall be expressed in permits as weekly average limitations.

NR 106.88(1)(b) (b) Effluent Limitations shall be expressed in a permit consistent with the protocols in s. NR 106.07 (3) to (5).

NR 106.88(1)(c) (c) Mass limitations calculated under s. NR 106.07 (2) and (9) shall be included in the permit in addition to concentration based effluent limitations whenever water quality-based effluent limitations are determined to be necessary.

NR 106.88(1)(d) (d) A compliance schedule for a water quality-based effluent for chloride may be granted in a permit if necessary and appropriate and shall be consistent with the requirements under s. NR 106.117.

NR 106.88(2) (2) Variance conditions. The department may include all of the following conditions in the permit instead of the conditions specified in sub. (1) whenever a chloride variance is granted under s. NR 106.83:

NR 106.88(2)(a) (a) Chloride monitoring.

NR 106.88(2)(b) (b) An interim limitation for chloride that is effective on the date of permit issuance.

NR 106.88(2)(c) (c) Tier 1 source reduction.

NR 106.88(2)(d) (d) A target value or a target limitation with an appropriate compliance schedule, which is effective on the last day of the permit.

NR 106.88(2)(e) (e) If appropriate, either tier 2 or tier 3 source reduction if the department believes that any of the additional conditions in the tier 2 or tier 3 source reduction activities are reasonable and practical within the term of the permit.

NR 106.88(3) (3) Units for target values. Interim limitations, target values, and target limitations established under sub. (2) shall be expressed in the permit as a concentration limitation, in units of mg/L or equivalent units.

NR 106.88(5) (5) Monitoring. A determination of compliance with interim, target, and calculated limitations and comparison with target values shall be based upon 24-hour composite samples. The department shall determine on a case-by-case basis the monitoring frequency to be required for these limitations.

NR 106.88 History History: Cr. Register, January, 2000, No. 529, eff. 2-1-00; CR 09-123: am. (3) Register July 2010 No. 655, eff. 8-1-10; CR 15-085: r. and recr. (1) to (3), r. (4), r. and recr. (5), r. (6) Register August 2016 No. 728, eff. 9-1-16.

NR 106.89 NR 106.89 Alternative whole effluent toxicity monitoring and limitations for dischargers of chloride.

NR 106.89(1) (1) General. In addition to interim, target, and calculated water quality-based effluent limitations and target values for chloride, the department may establish whole effluent toxicity testing requirements and limitations under ss. NR 106.08 and 106.09.

NR 106.89(2) (2) Findings. The department finds all of the following:

NR 106.89(2)(a) (a) Acute whole effluent toxicity limitations cannot be attained if the effluent concentration of chloride exceeds 2,500 mg/L.

NR 106.89(2)(b) (b) Chronic whole effluent toxicity limitations cannot be attained if the effluent concentration of chloride exceeds 2 times the calculated chronic water quality-based effluent limitation.

NR 106.89(2)(c) (c) If chloride is the sole source of acute or chronic whole effluent toxicity it is appropriate that chloride limitations be used instead of WET limitations to attain and maintain narrative criteria in s. NR 102.04 (1) (d) and (4) (d).

NR 106.89(3) (3) Chloride limits in lieu of acute wet limits. Chloride limitations shall be included in the permit in lieu of acute whole effluent toxicity testing requirements and acute whole effluent toxicity limitations until source reduction actions are completed if any of the following apply:

NR 106.89(3)(a) (a) The permittee can demonstrate to the satisfaction of the department that the effluent concentration of chloride exceeds 2,500 mg/L.

NR 106.89(3)(b) (b) The permittee can demonstrate to the satisfaction of the department that the effluent concentration of chloride is less than 2,500 mg/L, but in excess of the calculated acute water quality-based effluent limitation, and additional data are submitted that demonstrate that chloride is the sole source of acute toxicity.

NR 106.89(4) (4) Chloride limits in lieu of chronic wet limits. Chloride limitations shall be included in the permit in lieu of chronic whole effluent toxicity testing requirements and chronic whole effluent toxicity limitations until source reduction actions are completed if either of the following applies:

NR 106.89(4)(a) (a) The permittee can demonstrate to the satisfaction of the department that the effluent concentration of chloride exceeds 2 times the calculated chronic water quality-based effluent limitation.

NR 106.89(4)(b) (b) The permittee can demonstrate to the satisfaction of the department that the effluent concentration of chloride is less than 2 times the calculated chronic water quality-based effluent limitation, but in excess of the calculated chronic water quality-based effluent limitation, and additional data are submitted which demonstrate that chloride is the sole source of chronic toxicity.

NR 106.89(5) (5) Decision documentation. The department shall specify the decision to include chloride limitations instead of whole effluent toxicity limitations in the permit fact sheet.

NR 106.89(6) (6) Reevaluation. The department shall reevaluate the need for whole effluent toxicity and chloride monitoring or limitations upon permit reissuance.

NR 106.89 History History: Cr. Register, January, 2000, No. 529, eff. 2-1-00; CR 15-085: r. and recr. Register August 2016 No. 728, eff. 9-1-16; correction in (2) (c) made under s. 35.17, Stats., Register August 2016 No. 728.

NR 106.90 NR 106.90 Source reduction.

NR 106.90(1) (1) Introduction. A 3-tiered system of source reduction measures is established in ascending order of increasing capital and operating costs.

NR 106.90(2) (2) Tier 1 source reduction measures are those voluntary source reduction activities that identify and quantify chloride and softened water sources and usage, educate users and system operators on the need to minimize salt and softened water demands and promote better housekeeping practices that will reduce chloride and softened water consumption, and other activities similar in nature. Tier 1 source reduction measures may include any of the following:

NR 106.90(2)(a) (a) For POTWs:

NR 106.90(2)(a)1. 1. Identify sources of chloride to the sewer system.

NR 106.90(2)(a)2. 2. Educate homeowners on the impact of chloride from residential softeners, discuss options available for increasing softener salt efficiency, and request voluntary reductions.

NR 106.90(2)(a)3. 3. Recommend residential softener tune-ups on a voluntary basis.

NR 106.90(2)(a)4. 4. Request voluntary support from local water softening businesses in the efforts described in subds. 2. and 3.

NR 106.90(2)(a)5. 5. Educate licensed installers and self-installers of softeners on providing optional hard water for outside faucets for residences.

NR 106.90(2)(a)6. 6. Request voluntary reductions in chloride input from industrial and commercial contributors.

NR 106.90(2)(a)7. 7. Where a public water utility has been identified as a significant contributor of chloride to the sewer system, request that the water utility conduct activities listed in par. (b).