Chapter NR 210

NR 210.03(5)(a) (a) For a given pollutant parameter, the 95th percentile value for the 30-day average effluent quality achieved by a treatment works in a period of at least 2 years, excluding values attributable to upsets, bypasses, operational errors, or other unusual conditions, and

NR 210.03(5)(b) (b) A 7-day average value equal to 1.5 times the value derived under par. (a).

NR 210.03(6) (6) “Facilities eligible for treatment equivalent to secondary treatment” means treatment works which meet all of the following:

NR 210.03(6)(a) (a) The BOD5 and SS effluent concentrations consistently achievable through proper operation and maintenance of the treatment works exceed the minimum level of the effluent quality set forth in s. NR 210.05 (1) (a) and (b);

NR 210.03(6)(b) (b) Trickling filters, aerated lagoons or waste stabilization ponds are used as the principal processes; and

NR 210.03(6)(c) (c) The treatment works provide significant biological treatment of municipal wastewater.

NR 210.03(6e) (6e) “Hydraulic constraint” means the structural collapse of a sewer, an accumulation of material in a sewer or an insufficiently-sized sewer such that sewage flow is impeded or stopped from flowing downstream.

NR 210.03(6m) (6m) “Infiltration” has the meaning specified under s. NR 110.03 (16).

NR 210.03 Note Note: Section NR 110.03 (16) reads: “Infiltration” means water other than wastewater that enters a sewerage system (including sewer service connections) from the ground through such sources as defective pipes, pipe joints, connections, or manholes. Infiltration does not include, and is distinguished from, inflow.

NR 210.03(6s) (6s) “Inflow” has the meaning specified under s. NR 110.03 (17).

NR 210.03 Note Note: Section NR 110.03 (17) reads: “Inflow” means water other than wastewater that enters a sewerage system (including sewer service connections) from sources such as roof leaders, cellar drains, yard drains, area drains, foundation drains, sump pumps, drains from springs and swampy areas, manhole covers, cross connections between storm sewers and sanitary sewers, catch basins, cooling towers, storm waters, surface runoff, street wash waters, or drainage. Inflow does not include, and is distinguished from, infiltration.

NR 210.03(7) (7) “NH3-N” means ammonia nitrogen.

NR 210.03(8) (8) “Percent removal” means a percentage expression of the removal efficiency across a treatment plant for a given pollutant parameter, as determined from the 30-day average values of the raw wastewater influent pollutant concentrations to the facility and the 30-day average values of the effluent pollutant concentrations for a given time period.

NR 210.03(8m) (8m) “Private interceptor main sewer” has the meaning specified under s. NR 110.03 (26m).

NR 210.03 Note Note: Section NR 110.03 (26m) reads: “Private interceptor main sewer” means a sewer serving two or more buildings and not part of the municipal sewer system.

NR 210.03(9) (9) “Privately owned domestic sewage treatment works” means those facilities which treat domestic wastewater and are owned and operated by nonmunicipal entities or enterprises such as mobile home parks, restaurants, hotels, motels, country clubs, resorts, etc., which are permitted under ch. 283, Stats.

NR 210.03(10) (10) “Sanitary sewer overflow” means a release of wastewater from a sewage collection system or an interceptor sewer directly into a water of the state or to the land surface.

NR 210.03(10m) (10m) “Sanitary survey” means a thorough investigation and evaluation of a surface water including bacteriological sampling to determine the extent and cause of any bacterial contamination.

NR 210.03(11) (11) “Sewage collection system” has the meaning specified under s. NR 110.03 (28).

NR 210.03 Note Note: Section NR 110.03 (28) reads: “Sewage collection system” means the common sanitary sewers, interceptor sewers, and appurtenant equipment, such as lift stations, within a sewerage system which are primarily installed to receive wastewaters directly from facilities which convey wastewater from individual structures or from private property, and which include service connection “Y” fittings designed for connection with those facilities. The facilities which convey wastewater from individual structures such as building sewers and private interceptor sewers, from private property to the public sanitary sewer, or its equivalent, are specifically excluded from the definition of “sewage collection system”; except that pumping units and pressurized lines for individual structures or groups of structures are included as part of a “sewage collection system” when such units are cost effective and are owned and maintained by the sewerage system owner.

NR 210.03(12) (12) “Sewage treatment facility” has the meaning specified under s. NR 110.03 (29).

NR 210.03 Note Note: Section NR 110.03 (29) reads: “Sewage treatment facility” means all the structures, pipes and other equipment that constitute the various treatment processes and treatment units employed to reduce pollutants in sewage.

NR 210.03(13) (13) “Sewage treatment facility overflow” means a release of wastewater from a location within a sewage treatment facility, other than permitted effluent outfall structures, directly to a water of the state or to the land surface. A sewage treatment facility overflow does not include blending, controlled diversions or discharges from permitted combined sewage treatment facility effluent outfall structures.

NR 210.03(14) (14) “Sewer extension” has the meaning specified under s. NR 110.03 (29m).

NR 210.03 Note Note: Section NR 110.03 (29m) reads: “Sewer extension” means installation of a sewer or interceptor sewer, or extension thereof, to provide additional conveyance capacity and service to development within the existing or proposed tributary area of the extension. Alterations or modifications of existing sewerage systems designed to replace inadequate existing structures or installed because of inadequate hydraulic sewer capacity and that do not extend sanitary sewer service to areas previously not served are not sewer extensions.

NR 210.03(15) (15) “Sewerage system” has the meaning specified under s. NR 110.03 (30).

NR 210.03 Note Note: Section NR 110.03 (30) reads: “Sewerage system” means all structures, conduits and pipes, by which sewage is collected, treated, and disposed of, except plumbing inside and in connection with buildings served, and service pipes, from building to street main.

NR 210.03(16) (16) “Significant biological treatment” means the use of an aerobic or anaerobic biological treatment process in a treatment works to consistently achieve a 30-day average of at least 65% removal of BOD5.

NR 210.03 History History: Cr. Register, October, 1986, No. 370, eff. 11-1-86; CR 09-123: cr. (9m) Register July 2010 No. 655, eff. 8-1-10; CR 12-027: am. (intro.), cr. (2e), (2m), (2s), (3d), (3h), (3p), (3t), (6e), (6m), (6s), (8m), renum. (9m) to (12) and am., renum. (10) to (16), cr. (10), (11), (13) to (15) Register July 2013 No. 691, eff. 8-1-13; correction in (14) made under s. 13.92 (4) (b) 7., Stats., Register July 2013 No. 691; CR 19-014: (10m) renum. from NR 102.03 (6) Register April 2020 No. 772, eff. 5-1-20.

Subchapter II — Monitoring Requirements and
Effluent Limitations

NR 210.035 NR 210.035 Applicability. This subchapter applies to publicly owned treatment works and privately owned domestic sewage treatment works that discharge to surface waters.

NR 210.035 History History: CR 12-027: cr. Register July 2013 No. 691, eff. 8-1-13.

NR 210.04 NR 210.04 Monitoring requirements.

NR 210.04(1) (1) Discharges subject to the provisions of this chapter shall at a minimum monitor the effluent for BOD5, SS, and pH.

NR 210.04(2) (2) Influent wastewater strengths and volumes shall be characterized at treatment facilities subject to the monitoring provisions of sub. (1) by monitoring for flow, BOD5 and SS.

NR 210.04(3) (3) Monitoring requirements may be adjusted on a case-by-case basis depending on wastewater characteristics and their potential to degrade water quality.

NR 210.04(4) (4) The department shall require the use of 24-hour flow proportional samplers for monitoring influent and effluent wastewater quality except where the department determines through the permit issuance process that other sample types may adequately characterize the influent or effluent quality. In evaluating permit monitoring requirements, the department may consider:

NR 210.04(4)(a) (a) Treatment facility design flow and actual flow;

NR 210.04(4)(b) (b) Type of treatment processes used at the facility;

NR 210.04(4)(c) (c) Previous performance records as reported on the discharge monitoring report;

NR 210.04(4)(d) (d) Type of wastewater treated: domestic, municipal or industrial wastewater; and

NR 210.04(4)(e) (e) Final effluent limitations.

NR 210.04(5) (5) The methods of sampling shall be as described in s. NR 218.04 (10) to (17).

NR 210.04 History History: Cr. Register, October, 1986, No. 370, eff. 11-1-86.

NR 210.05 NR 210.05 Effluent limitations. Publicly owned treatment works and privately owned domestic sewage treatment works shall meet as a minimum the effluent limits specified in this section.

NR 210.05(1) (1) Where the receiving water is classified as fish and aquatic life in s. NR 102.04 (3):

NR 210.05(1)(a) (a) The following effluent limits for BOD5 apply:

NR 210.05(1)(a)1. 1. The 30-day average may not exceed 30 mg/l.

NR 210.05(1)(a)2. 2. The 7-day average may not exceed 45 mg/l.

NR 210.05(1)(a)3. 3. The 30-day average percent removal may not be less than 85%.

NR 210.05(1)(b) (b) The following effluent limits for SS apply:

NR 210.05(1)(b)1. 1. The 30-day average may not exceed 30 mg/l.

NR 210.05(1)(b)2. 2. The 7-day average may not exceed 45 mg/l.

NR 210.05(1)(b)3. 3. The 30-day average percent removal may not be less than 85%.

NR 210.05(1)(c) (c) The effluent pH shall be within the range of 6.0 to 9.0.

NR 210.05(1)(d) (d) Upon request by the permittee, pursuant to s. NR 210.07 (4), the department may substitute the parameter CBOD5 for the parameter BOD5 and the levels of effluent quality specified in par. (a). The following effluent quality levels of CBOD5 shall be applicable:

NR 210.05(1)(d)1. 1. The 30-day average may not exceed 25 mg/l.

NR 210.05(1)(d)2. 2. The 7-day average may not exceed 40 mg/l.

NR 210.05(1)(d)3. 3. The 30-day average percent removal may not be less than 85%.

NR 210.05(1)(e) (e) More stringent effluent limitations than those specified in pars. (a) to (d) may be imposed for any pollutant where necessary to meet water quality standards for water receiving the treated discharge.

NR 210.05(2) (2) Where the receiving water is classified as intermediate aquatic life as defined in s. NR 104.02 (3) (a):

NR 210.05(2)(a) (a) The following effluent limits for BOD5 apply:

NR 210.05(2)(a)1. 1. The 30-day average may not exceed 15 mg/l.

NR 210.05(2)(a)2. 2. The daily maximum may not exceed 30 mg/l.

NR 210.05(2)(a)3. 3. The 30-day average percent removal may not be less than 85%.

NR 210.05(2)(b) (b) The following effluent limits for SS apply:

NR 210.05(2)(b)1. 1. The 30-day average may not exceed 20 mg/l.

NR 210.05(2)(b)2. 2. The daily maximum may not exceed 30 mg/l.

NR 210.05(2)(b)3. 3. The 30-day average percent removal may not be less than 85%.

NR 210.05(2)(d) (d) The effluent pH shall be within the range of 6.0 to 9.0.

NR 210.05(2)(e) (e) The daily minimum effluent dissolved oxygen level shall be 4.0mg/l.

NR 210.05(2)(f) (f) Upon request by the permittee, pursuant to s. NR 210.07 (4),the department may substitute the parameter CBOD5 for the parameter BOD5 and the levels of effluent quality specified in par. (a). The following effluent quality levels of CBOD5 shall be applicable:

NR 210.05(2)(f)1. 1. The 30-day average may not exceed 12 mg/l.

NR 210.05(2)(f)2. 2. The daily maximum may not exceed 25 mg/l.

NR 210.05(2)(f)3. 3. The 30-day average percent removal may not be less than 85%.

NR 210.05(2)(g) (g) More stringent effluent limitations than those specified in pars. (a) to (f) may be imposed for any pollutant where necessary to meet water quality standards for water receiving the treated discharge.

NR 210.05(3) (3) Where the receiving water is classified as marginal surface water as defined in s. NR 104.02 (3) (b):

NR 210.05(3)(a) (a) The following effluent limits for BOD5 apply:

NR 210.05(3)(a)1. 1. The 30-day average may not exceed 20 mg/l.

NR 210.05(3)(a)2. 2. The 7-day average may not exceed 30 mg/l.

NR 210.05(3)(a)3. 3. The 30-day average percent removal may not be less than 85%.

NR 210.05(3)(b) (b) The following effluent limits for SS apply:

NR 210.05(3)(b)1. 1. The 30-day average may not exceed 20 mg/l.

NR 210.05(3)(b)2. 2. The 7-day average may not exceed 30 mg/l.

NR 210.05(3)(b)3. 3. The 30-day average percent removal may not be less than 85%.

NR 210.05(3)(c) (c) The effluent pH shall be within the range of 6.0 to 9.0.

NR 210.05(3)(d) (d) The daily minimum effluent dissolved oxygen level shall be 4.0mg/l.

NR 210.05(3)(e) (e) Upon request by the permittee, pursuant to s. NR 210.07 (4),the department may substitute the parameter CBOD5 for the parameter BOD5 and the levels of effluent quality specified in par. (a). The following effluent quality levels of CBOD5will be applicable:

NR 210.05(3)(e)1. 1. The 30-day average may not exceed 16 mg/l.