NR 106.32(2)(d)2. 2. The department may allow a permittee to chemically adjust effluent pH to a lower value for the purpose of obtaining a higher ammonia effluent limitation. The adjusted pH shall be used to calculate the ammonia effluent limitation. The pH value of an effluent may not be adjusted to less than 6.0. Whenever the effluent pH is adjusted, the department may require continuous monitoring of the pH of the effluent.

NR 106.32(2)(d)3. 3. The department may establish an alternative pH for calculating the limitation under this section to protect downstream uses whenever the receiving water pH is significantly different from the effluent, or if a zone of initial dilution is applicable based on par. (c).

NR 106.32(2)(e) (e) To assure compliance with par. (a), the department may calculate acute water quality-based effluent limitations using the following procedure if the department concludes that limitations calculated in par. (b) or (c) are not sufficiently protective of fish and aquatic life. The department may include the calculated WQBEL in a permit if this limitation is more stringent than the limitation calculated in par. (b) or (c):

Limitation = (WQC) (Qs+(1-f)Qe) - (Qs- fQe) (Cs)
Qe

- See PDF for table

NR 106.32(3) (3) Limitations based on chronic toxicity or long-term impacts.

NR 106.32(3)(a) (a) Water quality criteria. The department shall calculate water quality based effluent limitations for ammonia to ensure that the chronic toxicity criteria applicable to the receiving water as specified in chs. NR 102 to 105 will be met after taking into account dilution with an appropriate quantity of receiving water flow allowed in this subsection. The available dilution shall be determined according to par. (c) unless the conditions specified in s. NR 102.05 (3) require less dilution or no dilution be allowed. The chronic toxicity criteria to be used in the calculation of ammonia effluent limitations shall apply as follows:

NR 106.32(3)(a)1. 1. The applicable early life stages present ammonia criteria in s. NR 105.05 Table 4B shall be used to calculate effluent limitations for all times of the year for all discharges to Class I and Class II trout waters, as identified by the department’s Wisconsin Trout Streams publication referenced in s. NR 102.04 (3) (a), and any additional Class I and Class II trout waters identified in ss. NR 102.10 (1) (d) and (e), and 102.11 (1) (b) and (c).

NR 106.32(3)(a)2. 2. The applicable early life stages present ammonia criteria in s. NR 105.05 Table 4B shall be used to calculate effluent limitations for all discharges to all waters supporting warm water sport fish and warm water forage fish during the month of April or whenever the receiving water temperature, as determined in s. NR 106.32 (4), is greater than or equal to 14.6 degrees Celsius.

NR 106.32 Note Note: Effluent limitations are determined based on monthly average water temperatures determined from historical records. For many waters supporting warmwater fish species, the monthly average water temperature is 14.6 degrees Celsius or greater during the months of May through September.

NR 106.32(3)(a)3. 3. Except as provided in subd. 4., the applicable early life stage absent ammonia criteria in s. NR 105.05 Table 4B shall be used to calculate effluent limitations for all discharges to all waters supporting warm water sport fish and warm water forage fish whenever the receiving water temperature, as determined in s. NR 106.32 (4), is less than 14.6 degrees Celsius, but not including the month of April.

NR 106.32(3)(a)4. 4. The applicable early life stages present ammonia criteria in s. NR 105.05 Table 4B shall be used to calculate effluent limitations applicable for the months of January, February, and March for all discharges to waters where the department determines that early life stages of burbot are present.

NR 106.32 Note Note: Burbot are not present in limited aquatic life streams, limited forage fish streams and small or shallow headwater streams and rivers.

NR 106.32(3)(a)4.a. a. Whenever the department determines that early life stage present ammonia criteria are applicable under this subdivision, the permittee may make a demonstration that the early life stages of burbot are not present at the discharge location and will not be affected by the discharge during the months of January and February. If the department grants approval for an alternative limitation based on results of this study, the department shall include the alternative limitation in a permit modification or reissuance provided antidegradation requirements in ch. NR 207 have been satisfied.

NR 106.32(3)(a)4.b. b. If the permittee can demonstrate to the satisfaction of the department that the early life stages of burbot are not present at the discharge location and will not be affected by the discharge, the early life stage absent ammonia criteria in s. NR 105.05 Table 4B shall be used to calculate effluent limitations that apply to the permittee and the department shall propose a permit modification to incorporate the limitations. If the permittee does not make a sufficient demonstration, the early life present ammonia criteria in s. NR 105 Table 4B shall apply.

NR 106.32(3)(a)5. 5. The applicable early life stages present ammonia criteria in s. NR 105.05 Table 4B shall be used to calculate effluent limitations for the months of May through September for all discharges to waters designated in ch. NR 104 as limited forage fish waters. The early life stages absent ammonia criteria in s. NR 105.05 Table 4B shall be used to calculate effluent limitations for the months of October through April for all discharges to waters designated in ch. NR 104 as limited forage fish waters.

NR 106.32(3)(a)6. 6. The applicable ammonia criteria in s. NR 105.05 Table 4B shall be used to calculate effluent limitations for all discharges to waters designated in ch. NR 104 as limited aquatic life waters.

NR 106.32(3)(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 s. NR 106.06 (6).

NR 106.32(3)(b)1. 1. For discharges of ammonia to flowing receiving waters, the water quality based effluent limitation shall be calculated using the following conservation of mass equation whenever the background concentration is less than the water quality criterion:

Limitation = (CTC) (Qs + (1-f)Qe) - (Qs - fQe) (Cs)
Qe

Where:

Limitation = Water quality based effluent limitation (in units of mass per unit of volume)

CTC =   The chronic toxicity criterion (concentration in units of mass per unit volume) as referenced in par. (a)

Qs =   Receiving water design flow (in units of volume per unit time) as specified in par. (c)

Qe =   Effluent flow (in units of volume per unit time) as specified in par. (d)

f =   Fraction of the effluent flow that is withdrawn from the receiving water

Cs =   Background concentration of ammonia (in units of mass per unit volume) as specified in par. (e)

NR 106.32 Note Note: In applying this equation, all units for the flow and concentration parameters respectively shall be consistent.

NR 106.32(3)(b)2. 2. For discharges of ammonia 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: