Chapter NR 210

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.

NR 210.05(3)(e)2. 2. The 7-day average may not exceed 25 mg/l.

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

NR 210.05(3)(f) (f) More stringent effluent limitations than those specified in pars. (a) to (e) may be imposed for any pollutant where necessary to meet water quality standards for water receiving the treated discharge.

NR 210.05(4) (4) Effluent limitations may be imposed for pollutants other than those specified in subs. (1) to (3) where necessary to meet water quality standards for waters receiving the treated discharge.

NR 210.05(5) (5) When determining whether more stringent effluent limitations are required under this section to meet water quality standards in the receiving water or downstream waters, the department shall apply the reasonable potential procedures in s. NR 205.067.

NR 210.05 History History: Cr. Register, October, 1986, No. 370, eff. 11-1-86; CR 03-050: r. (2) (c) Register February 2004 No. 578, eff. 3-1-04; correction in (1) (intro.) made under s. 13.93 (2m) (b) 7., Stats., Register February 2004 No. 578; CR 17-002: cr. (5) Register April 2018 No. 748, eff. 5-1-18.

NR 210.06 NR 210.06 Disinfection requirements.

NR 210.06(1) (1) Disinfection requirements. Disinfection shall be required of dischargers subject to the provisions of this chapter when the department determines, based on the information identified in sub. (3), the discharge of wastewater poses a risk to human and animal health. Disinfection shall be required:

NR 210.06(1)(a) (a) From May 1 through September 30 annually to protect recreational uses, or

NR 210.06(1)(b) (b) Year-round to protect public drinking water supplies.

NR 210.06(1)(c) (c) The period during which disinfection under pars. (a) and (b) is required may be adjusted in a WPDES permit where necessary to protect human and animal health.

NR 210.06(2) (2) Effluent limitations. Where and when disinfection is required, the following effluent limitations shall apply:

NR 210.06(2)(a) (a) Bacterial indicators.

NR 210.06(2)(a)1. 1. ‘Recreation protection.’ During the period of disinfection to protect recreational uses as determined under sub. (1) (a) or (c), all of the following shall apply:

NR 210.06(2)(a)1.a. a. The geometric mean of E. coli bacteria in effluent samples collected in any calendar month may not exceed 126 counts/100 mL.

NR 210.06 Note Note: To calculate the geometric mean, a value of 1 should be used for any result of 0.

NR 210.06 Note Note: As specified in ch. NR 102, Table A, for determining attainment or compliance with bacteria criteria or limits, counts are equivalent to either colony forming units or most probable number.

NR 210.06(2)(a)1.b. b. No more than 10 percent of E. coli bacteria samples collected in any calendar month may exceed 410 counts/100 mL.

NR 210.06 Note Note: U.S. EPA developed the E. coli criteria in s. NR 102.04 (6), on which these effluent limits are based using membrane filtration to count E. coli colony forming units.

NR 210.06(2)(a)2. 2. ‘Public drinking water supply protection.’ If a facility is required to disinfect to protect public drinking water supplies outside of the recreation period specified in sub. (1) (a) or (c), it may either continue to meet the E. coli limits specified in par. (a) 1. year-round, or the geometric mean of the fecal coliform bacteria for effluent samples collected in a period of 30 consecutive days may not exceed 400 counts/100 mL.

NR 210.06(2)(b) (b) Chlorine. When chlorine is used for disinfection, the daily maximum total residual chlorine concentration of the discharge may not exceed 0.1mg/l. In addition, when chlorine is used for disinfection, a dechlorination process shall be in operation for the period during which disinfection is required.