Wis. Admin. Code Department of Natural Resources § NR 205.065 - Effluent Limitations

(1) EFFLUENT LIMITATIONS IN PERMITS. The department shall impose permit effluent limitations or effluent standards for discharges of pollutants on the discharge point of the permitted facility except as provided in sub. (2).

(2) INTERNAL WASTE STREAMS. The department may impose permit effluent limitations or effluent standards for discharges of pollutants on an internal waste stream when all of the following are true:

(a) Imposing effluent limitations or standards at the point of discharge is impractical or infeasible.

(b) The internal waste stream has not mixed with other waste streams or cooling water streams.

(c) The fact sheet under ch. NR 201 states the reasons why it is necessary to impose effluent limitations or standards on an internal waste stream.

(3) CALCULATION OF EFFLUENT LIMITATIONS FOR POTWS. For continuous dischargers as defined in s. NR 205.03(9g) and subject to ch. NR 210, effluent limitations shall be based on 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.

(4) CALCULATION OF EFFLUENT LIMITATIONS FOR OTHER CONTINUOUS DISCHARGES. For all other discharges not subject to ch. NR 210, effluent limitations shall be calculated based on actual representative flow values except as provided in pars. (a) and (b).

(a) For new discharges, production-based effluent limitations shall be estimated using projected production.

(b) If a facility is expanding or decreasing production levels, the department may use an estimated alternative production value to calculate production-based effluent limitations.

(5) INTAKE WATER CREDIT. If requested by the permittee in the permit application for issuance or reissuance, technology-based effluent limitations shall, for each substance or parameter, be adjusted to reflect the discharger's intake water if all of the following conditions are met:

(a) Antidegradation requirements in ch. NR 207 are satisfied, if applicable.

(b) The permittee does not discharge raw water clarifier sludge generated from the treatment of intake water.

(c) The permittee demonstrates that the applicable technology-based effluent limitation for the pollutant would be met in the absence of the pollutant in the intake water.

(d) The permittee demonstrates that the constituents of the pollutant in the effluent are substantially similar to the constituents of the pollutant in the intake water. The permittee shall also demonstrate that the intake water is drawn from the same waterbody as defined in s. NR 106.03(11m) from into which the discharge is made.

(6) MAXIMUM INTAKE WATER CREDIT. If intake credit is granted pursuant to sub. (5), that intake credit cannot exceed the maximum value equal to the influent value, and shall be no greater than the value necessary to comply with the applicable permit effluent limitation. Additional monitoring may be included in the permits to determine eligibility for credits and compliance with the applicable limits.

(7) EFFLUENT LIMIT EXPRESSION. Effluent limitations shall be expressed in accordance with this subsection except if the department determines it is impracticable, or if the department determines that different time periods for expressing limitations are needed to ensure compliance with the applicable water quality standard and different time periods are established in another rule provision for a specific pollutant. Water quality-based effluent limitations for toxic pollutants shall be expressed in a permit in accordance with ch. NR 106. Effluent limitations shall be expressed in accordance with all of the following:

(a) For continuous dischargers as defined in s. NR 205.03(9g) and subject to ch. NR 210, limitations shall be expressed as average weekly and average monthly discharge limitations.

(b) For continuous discharges as defined in s. NR 205.03(9g) and not subject to ch. NR 210, limitations shall be expressed as daily maximum and average monthly discharge limitations.

(c) For seasonal discharges, discharges proportional to stream flow, or other unusual discharge situations that do not meet the definition of a continuous discharge in s. NR 205.03(9g), limitations shall be expressed on a case-by-case basis. When determining limitations the department shall consider all of the following factors:

1. Frequency and duration of discharge.

2. Total mass of discharge.

3. Maximum flow rate of discharge.

4. Whether the pollutant is subject to other limitations expressed by mass, concentration, or other appropriate measure in the permit.

Note: An example of a different time period for expressing limits for a specific pollutant or parameter is phosphorus limitations as specified in s. NR 217.14.

(8) MASS LIMITATIONS.

(a) All pollutants limited in permits shall have limitations, standards, or prohibitions expressed in terms of mass, except for any of the following situations:

1. Pollutants limited in permits that cannot be appropriately expressed by mass such as pH, chlorine, temperature, radiation, or other pollutants.

2. When applicable standards and limitations are expressed in terms of other units of measurement.

3. If limitations expressed in terms of mass are infeasible because the mass of the pollutant discharged cannot be related to a measure of operation.

(b) If a mass limit is included in the permit for a pollutant, the pollutant may also be limited in terms of other units of measurement in the permit, and the permit shall require the permittee to comply with both limitations.

(9) METALS. All permit effluent limitations, standards, or prohibitions for a metal shall be expressed in terms of total recoverable in a permit unless any of the following conditions apply:

(a) An applicable effluent standard or limitation has been promulgated and specifies the limitation for the metal in dissolved or valent or total form.

(b) In establishing permit limitations on a case-by-case basis, it is necessary to express the limitation for the metal in the dissolved or valent or total form to carry out the provisions of the federal Clean Water Act or ch. 283, Stats.

(c) All approved analytical methods for the metal inherently measure only the dissolved form of the pollutant.

Notes

Wis. Admin. Code Department of Natural Resources § NR 205.065

Adopted by, CR 15-085: cr. Register August 2016 No. 728, eff. 9/1/2016