Chapter NR 211

NR 211.03(4) (4) “Control authority” means the POTW in relation to POTWs which have a pretreatment program and means the department in relation to POTWs which do not have a pretreatment program.

NR 211.03(4m) (4m) “EPA” means the U.S. environmental protection agency.

NR 211.03(5) (5) “Existing source” means any source which is not a new source.

NR 211.03(6) (6) “Indirect discharge” means the introduction of pollutants into a POTW from any point source other than residential or commercial sources that discharge only domestic waste. Method of introduction includes, but is not limited to, by pipe, truck, or rail car.

NR 211.03(7) (7) “Industrial user” means any source of indirect discharge.

NR 211.03(8) (8) “Interference” means the inhibition or disruption of a POTW’s sewer system, treatment processes, or operations by an indirect discharge which, alone or in conjunction with the discharge or discharges from other sources, causes a violation or increases the magnitude or duration of a violation of any requirement of the POTW’s WPDES permit, or impairs the use or disposal of POTW sludge under chs. 281 and 283, Stats.

NR 211.03(8m) (8m) “Maximum allowable industrial loading” means the total mass of a pollutant that all industrial users of a POTW, or groups of industrial users identified by the POTW, may discharge pursuant to local limits developed under s. NR 211.10 (3).

NR 211.03(9) (9) “New source” means any building, structure, facility, or installation:

NR 211.03(9)(a) (a) That discharges or may discharge pollutants;

NR 211.03(9)(b) (b) For which the commencement of construction occurred after the publication in the federal register of proposed pretreatment standards that will be applicable if promulgated according to section 307 (c) of the federal clean water act, 33 USC 1251 et seq.; and

NR 211.03(9)(c) (c) That is one of the following:

NR 211.03(9)(c)1. 1. Constructed at a site at which no other source is located;

NR 211.03(9)(c)2. 2. A total replacement of the process or production equipment that causes the discharge of pollutants at an existing source; or

NR 211.03(9)(c)3. 3. Substantially independent from an existing source at the same site. Whether or not a source is substantially independent shall be determined based on, among other factors, the extent to which the new facility is engaged in the same general type of activity as the existing source, and the extent to which the new facility’s production and wastewater generation are integrated with the existing source.

NR 211.03(9m) (9m) “Overflow” means any diversion of flow from a POTW before the POTW treatment plant.

NR 211.03(10) (10) “Pass through” means the discharge of pollutants through the POTW to waters of the state in quantities or concentrations which, alone or in conjunction with the discharge or discharges from other sources, causes a violation or increases the magnitude or duration of a violation of any requirement of the POTW’s WPDES permit.

NR 211.03(11) (11) “POTW” or “Publicly owned treatment works” means a treatment works which is owned by a municipality and any sewers that convey wastewater to such a treatment works. This definition includes any devices or systems used by a municipality in the storage, treatment, recycling, and reclamation of municipal sewage or liquid industrial wastes. The term also means the municipality or local unit of government which has jurisdiction over the indirect discharges to, and the discharges from, such a treatment works.

NR 211.03(12) (12) “POTW treatment plant” means that portion of the POTW which is designed to provide treatment, including recycling and reclamation, of municipal sewage and industrial waste.

NR 211.03(13) (13) “Pretreatment” means the reduction of the amount of pollutants, the elimination of pollutants, or the alteration of the nature of pollutant properties in wastewater to a less harmful state prior to, or in lieu of, discharging such pollutants into a POTW.

NR 211.03(14) (14) “Pretreatment program” means a program administered by a POTW that meets the criteria established in subch. II and which has been approved by the department in accordance with subch. III.

NR 211.03(15) (15) “Pretreatment requirement” means any substantive or procedural requirement related to pretreatment, other than a pretreatment standard, imposed on an industrial user.

NR 211.03(16) (16) “Pretreatment standard” means any regulation which applies to industrial users and which contains pollutant discharge limits promulgated by the department in accordance with s. 283.21 (2), Stats. This term includes both prohibited discharge standards set forth in or established under s. NR 211.10 and categorical pretreatment standards set forth in s. NR 211.11 and in chs. NR 221 through 297.

NR 211.03(17) (17) “Prohibited discharge standard” means any standard specifying quantities or concentrations of pollutants or pollutant properties which may be discharged to a POTW by industrial users regardless of industrial category.

NR 211.03(18) (18) “Regulated stream” means a stream regulated by a categorical pretreatment standard.

NR 211.03(19) (19) “Removal” means a reduction in the amount of a pollutant in the POTW’s effluent or alteration of a pollutant during treatment at the POTW. The reduction or alteration may be physical, chemical or biological and may be the result of designed POTW capabilities or incidental to the operation of the treatment system. Removal does not mean dilution of a pollutant in the POTW.

NR 211.03(19m) (19m) “Significant industrial user” means:

NR 211.03(19m)(a) (a) Any industrial user subject to the categorical pretreatment standards in chs. NR 221 to 297, except as provided in s. NR 211.15 (4) (d);

NR 211.03(19m)(b) (b) Any industrial user which discharges an average of 25,000 gallons per day or more of wastewater to the POTW, excluding sanitary, noncontact cooling and boiler blowdown wastewater;

NR 211.03(19m)(c) (c) Any industrial user that discharges to the POTW a process waste stream which makes up 5% or more of the average dry weather hydraulic or organic capacity of the POTW treatment plant; or

NR 211.03(19m)(e) (e) Any other industrial user designated as a significant industrial user by the control authority.

NR 211.03(20) (20) “Sludge requirements” means the following statutory provisions and regulations or permits issued pursuant to them: section 405 of the federal clean water act; 33 USC 1251 et seq.; the solid waste disposal act (SWDA), 42 USC 6901 et seq.; the federal clean air act, 42 USC 1857 et seq.; the toxic substances control act, 15 USC 2601 et seq.; the marine protection, research and sanctuaries act, 33 USC 1401 et seq.; and ch. 281, Stats.

NR 211.03(20m) (20m) “Slug” means any nonroutine, episodic discharge, such as a discharge resulting from a spill or a noncustomary batch discharge.

NR 211.03(21) (21) “Unregulated stream” means a stream not regulated by a categorical pretreatment standard.

NR 211.03(22) (22) “WPDES permit” means a permit issued to a POTW under s. 283.31, Stats., for the purposes of controlling pollutant discharge.

NR 211.03 History History: Cr. Register, July, 1983, No. 331, eff. 8-1-83; r. (6), renum. (1) to (5) and (7) to (15) to be (2), (4), (6) to (8) and (10) to (17) and (22), cr. (1), (3), (5), (9) and (18) to (21), Register, September, 1986, No. 369, eff. 10-1-86; cr. (1m), (2e), (2s), (9m), (19m) and (20m), am. (8) and (10), r. and recr. (9), Register, March, 1992, No. 435, eff. 4-1-92; CR 13-006: cr. (1e), (4m), am. (8), cr. (8m), am. (16), (19m) (a), (c), r. (19m) (d) Register January 2014 No. 697, eff. 2-1-14; correction in (16) made under s. 13.92 (4) (b) 7., Stats., Register January 2014 No. 697.

subch. I of ch. NR 211 Subchapter I — Industrial User Requirements

NR 211.10 NR 211.10 Prohibited discharge standards.

NR 211.10(1) (1) Industrial users may not discharge pollutants into a POTW which pass through or interfere with the operation or performance of the POTW, and thereby cause or significantly contribute to a violation of the POTW’s WPDES permit.

NR 211.10(2) (2) The following pollutants may not be introduced into a POTW:

NR 211.10(2)(a) (a) Pollutants that create or contribute to a fire or explosion hazard in the POTW, including waste streams with a closed cup flashpoint of less than 140° F or 60° C using the test methods in s. NR 661.0021.

NR 211.10(2)(b) (b) Pollutants which will cause or contribute to corrosive structural damage to the POTW but in no case discharges with a pH lower than 5.0, unless the POTW is specifically designed to accommodate such discharges.

NR 211.10(2)(c) (c) Solid or viscous pollutants in amounts which will cause or contribute to obstruction to the flow in sewers or other interference with the operation of the POTW.

NR 211.10(2)(d) (d) Any pollutant, including oxygen demanding pollutants, released in a discharge of such volume or strength as to cause or contribute to interference in the POTW.

NR 211.10(2)(e) (e) Heat in amounts which will inhibit or contribute to the inhibition of biological activity in the POTW treatment plant resulting in interference or causing damage to the POTW but in no case heat in such quantities that the temperature exceeds 40°C (104°F) at the influent to the POTW treatment plant unless the department, at the request of the POTW, has approved alternate temperature limits.

NR 211.10(2)(f) (f) Petroleum oil, nonbiodegradable cutting oil or products of mineral oil origin in amounts that will cause interference or pass through.

NR 211.10(2)(g) (g) Pollutants which result in the presence of gases, vapors or fumes within the POTW in a quantity which may cause acute worker health or safety problems.

NR 211.10(2)(h) (h) Any trucked or hauled pollutants, except at discharge points designated by the POTW.

NR 211.10(3) (3) 

NR 211.10(3)(a) (a) POTWs developing pretreatment programs under subchapter II shall develop specific prohibited discharge standards to enforce the general prohibitions of subs. (1) and (2). All other POTWs shall, where the contributions of industrial users result in pass-through or interference and the resulting permit violation is likely to recur, develop and enforce specific prohibited discharge standards which, together with appropriate POTW facility or operation changes, are necessary to ensure continued compliance with the POTW’s WPDES permit.

NR 211.10(3)(b) (b) This subsection is not intended to require pretreatment as a substitute for adequate municipal treatment.

NR 211.10(3)(c) (c) Specific prohibited discharge standards may not be developed and enforced by the POTW without giving prior notice to persons or groups who have requested notice and an opportunity to respond.

NR 211.10(3)(d) (d) Where specific prohibited discharge standards or limits on pollutants or pollutant parameters are developed by a POTW under this subsection, they shall be deemed pretreatment standards for the purposes of s. 283.21 (2), Stats.

NR 211.10(3)(e) (e) POTWs may develop best management practices to implement the prohibitions of subs. (1) and (2). Such BMPs shall be considered specific prohibited discharge standards under this subsection and pretreatment standards for the purposes of s. 283.21 (2), Stats.

NR 211.10(4) (4) Except where expressly authorized to do so by an applicable pretreatment standard or requirement, no industrial user may increase the use of process water or in any other way attempt to dilute a discharge as a partial or complete substitute for adequate treatment to achieve compliance with a pretreatment standard or requirement. The control authority may impose mass limitations on an industrial user to account for dilution or in any other situation for which the control authority finds mass limitations appropriate.

NR 211.10 History History: Cr. Register, July, 1983, No. 331, eff. 8-1-83; r. (1) (a) and (b), am. (2) (a), cr. (2) (f) to (h) and (4), Register, March, 1992, No. 435, eff. 4-1-92; correction in (2) (a) made under s. 13.92 (4) (b) 7., Stats., Register May 2011 No. 665; CR 13-006: am. (3) (d), cr. (3) (e) Register January 2014 No. 697, eff. 2-1-14; CR 19-082: am. (2) (a) Register July 2020 No. 775, eff. 8-1-20.

NR 211.11 NR 211.11 Categorical pretreatment standards.

NR 211.11(1) (1) Categorical pretreatment standards for specific point source categories are set forth in chs. NR 221 to 297. Limits in categorical pretreatment standards shall apply to the effluent from the process regulated by the standard, unless otherwise specified in the standard. Limits in categorical pretreatment standards shall apply to wastestreams which are transported off-site for disposal as well as those discharged on-site. Industrial users shall comply with applicable categorical pretreatment standards, in addition to complying with the general prohibitions established in s. NR 211.10, unless specifically noted otherwise in the categorical pretreatment standard.

NR 211.11(2) (2) Compliance dates.

NR 211.11(2)(a) (a) All industrial users, except new sources, shall comply with the applicable categorical pretreatment standards within 3 years from the effective date of the standard or within a shorter time period if specified in the applicable standard. A direct discharger which becomes an industrial user after promulgation of an applicable categorical pretreatment standard may not be considered a new source unless it falls within the definition of a “new source”contained in s. NR 211.03 (9).

NR 211.11(2)(b) (b) New sources shall install, have in operating condition and start up all of the pollution control equipment required to meet the applicable pretreatment standards before beginning discharge. Within the shortest feasible time, not to exceed 90 days, new sources shall meet all applicable pretreatment standards.

NR 211.11(3) (3) Conversion to equivalent mass or concentration standards.

NR 211.11(3)(a) (a)

NR 211.11(3)(a)1. 1. When the limits in a categorical pretreatment standard are expressed only in terms of mass of pollutant per unit of production, the control authority may convert the limits to equivalent limitations expressed either as mass of pollutant discharged per day or effluent concentration for purposes of calculating limits for individual users.

NR 211.11(3)(a)2. 2. Equivalent mass per day limits shall be calculated by multiplying the limits in the standard by the industrial user’s average rate of production. This average rate of production shall be based upon a reasonable measure of the industrial user’s actual long-term daily production, such as average daily production, during a representative year. For new sources, actual production shall be estimated using projected production.

NR 211.11(3)(a)3. 3. Equivalent concentration limits shall be calculated by dividing the mass limits derived according to subd. 2. by the average daily flow rate of the industrial user’s process wastewater. This average daily flow rate shall be based upon a reasonable measure of the industrial user’s actual long-term average flow rate, such as the average daily flow rate during the same representative year used in subd. 2.

NR 211.11(3)(a)4. 4. When pretreatment standards specify both daily and long-term limits, the same production or flow figures shall be used in calculating daily and long-term equivalent limits.

NR 211.11(3)(a)5. 5. Any industrial user operating under a control mechanism incorporating equivalent mass or concentration limits calculated from a production based standard shall notify the control authority within 2 business days after the industrial user has reason to know that the production level will significantly change within the next calendar month. Any industrial user which does not notify the control authority of such anticipated change shall meet the mass or concentration limits in its control mechanism that were based on the original estimate of the long-term average production rate.

NR 211.11(3)(bm) (bm)

NR 211.11(3)(bm)1. 1. When the limits in a categorical pretreatment standard are expressed only in terms of pollutant concentrations, an industrial user may request that the control authority convert the limits to equivalent mass limits. The determination to convert concentration limits to mass limits is within the discretion of the control authority. The control authority may establish equivalent mass limits only if the industrial user:

NR 211.11(3)(bm)1.a. a. Employs or demonstrates that it will employ water conservation methods and technologies that substantially reduce water use during the term of its control mechanism;

NR 211.11(3)(bm)1.b. b. Uses control and treatment technologies that are adequate to achieve compliance with the applicable categorical pretreatment standard, and has not used dilution as a substitute for treatment;

NR 211.11(3)(bm)1.c. c. Provides sufficient information to establish the facility’s actual average daily flow rate for all waste streams, based on data from a continuous effluent flow monitoring device, as well as the facility’s long-term average production rate. Both the actual average daily flow rate and the long-term average production rate shall be representative of current operating conditions;

NR 211.11(3)(bm)1.d. d. Does not have daily flow rates, production levels, or pollutant levels that vary so significantly that equivalent mass limits are not appropriate to control the discharge; and

NR 211.11(3)(bm)1.e. e. Has consistently complied with all applicable categorical pretreatment standards during the period prior to the industrial user’s request for equivalent mass limits.

NR 211.11(3)(bm)2. 2. Upon approval by the control authority an industrial user subject to equivalent mass limits shall:

NR 211.11(3)(bm)2.a. a. Maintain and effectively operate control and treatment technologies adequate to achieve compliance with the equivalent mass limits;

NR 211.11(3)(bm)2.b. b. Continue to record the facility’s flow rates through the use of a continuous effluent flow monitoring device;

NR 211.11(3)(bm)2.c. c. Continue to record the facility’s production rates and notify the control authority whenever production rates are expected to vary by more than 20 percent from its baseline production rates determined in subd. 1. c. Upon notification of a revised production rate, the control authority shall reassess the equivalent mass limit and revise the limit as necessary to reflect changed conditions at the facility; and

NR 211.11(3)(bm)2.d. d. Continue to employ the same or comparable water conservation methods and technologies as those implemented pursuant to subd. 1. a. so long as it discharges under an equivalent mass limit.

NR 211.11(3)(bm)3. 3. A control authority which chooses to establish equivalent mass limits:

NR 211.11(3)(bm)3.a. a. Shall calculate the equivalent mass limit by multiplying the actual average daily flow rate of the regulated processes by the concentration-based daily maximum and monthly average standard for the applicable categorical pretreatment standard and the appropriate unit conversion factor;

NR 211.11(3)(bm)3.b. b. Upon notification of a revised production rate, shall reassess the equivalent mass limit and recalculate the limit as necessary to reflect changed conditions at the facility; and

NR 211.11(3)(bm)3.c. c. May retain the same equivalent mass limit in subsequent control mechanism terms if the industrial user’s actual average daily flow rate was reduced solely as a result of the implementation of water conservation methods and technologies, and the actual average daily flow rates used in the original calculation of the equivalent mass limit were not based on the use of dilution as a substitute for treatment as prohibited by s. NR 211.10 (4). The industrial user shall also be in compliance with s. NR 211.19.

NR 211.11(3)(bm)4. 4. A control authority may not express limits in terms of mass for pollutants such as pH, temperature, radiation, or other pollutants which cannot appropriately be expressed as mass.

NR 211.11(3)(cm) (cm) The control authority may convert the mass limits of the categorical pretreatment standards in chs. NR 233, 235, and 279 to equivalent concentration limits. When converting such limits to concentration limits, the control authority shall use the concentrations listed in the applicable subparts of chs. NR 233, 235, and 279 and document that dilution is not being substituted for treatment as prohibited by s. NR 211.10 (4).

NR 211.11(3)(d) (d) Equivalent limitations calculated in accordance with par. (a), (bm), or (cm) are deemed pretreatment standards for the purposes of this chapter and s. 283.21 (2), Stats. The control authority shall document how the equivalent limits were derived and make this information available to the public. Once incorporated into its control mechanism, the industrial user shall comply with the equivalent limitations in lieu of the promulgated categorical standards from which the equivalent limitations were derived.

NR 211.11(3)(e) (e) When pretreatment standards specify both maximum daily and maximum average limits, the same production or flow figures shall be used in calculating maximum daily and maximum average limits.

NR 211.11(4) (4) Compensation for pollutants in intake water.

NR 211.11(4)(a) (a) Categorical pretreatment standards may be adjusted to reflect the presence of pollutants in an industrial user’s intake water if the applicable categorical pretreatment standards specifically provide that they may be applied on a net basis or if the industrial user demonstrates to the control authority that: