NR 811.858(1)(d)(d) A minimum of 2 cells to provide flexibility in operation. The inlet and outlet structures shall be designed so that the cells may be operated independently.

NR 811.858(1)(h)(h) Supernatant from lagoon thickening shall be discharged to a sanitary sewer, water of the state, or holding tank, under the applicable requirements of s. NR 811.85 (1). Lime softening sludge supernatant that is discharged to a water of the state shall meet the treatment requirements under s. NR 811.857 (3).

NR 811.858(2)(2) Application to agricultural land. The department may allow liquid sludge to be applied to agricultural land by tank truck. This method requires proper handling facilities, vehicles, and equipment to allow hauling and spreading that does not create dust, odors, or other nuisance conditions. Adequate sludge holding facilities are required for use during times that trucks cannot operate. Land application of sludge, including the radionuclide content, shall comply with s. NR 811.85 (1) (b).

NR 811.858 NoteNote: Under s. NR 214.02 (3) (k), uncontaminated lime sludges from water supply treatment facilities shall follow the land spreading requirements under s. NR 518.04 (3). Uncontaminated lime sludges exclude any sludges containing radionuclide content that are regulated under a WPDES permit under ch. 283, Stats. The department’s wastewater program in the bureau of water quality is responsible for the issuance of WPDES permits for discharges from waterworks to a water of the state. Waterworks owners should contact the department’s district wastewater staff for WPDES permit application and compliance requirements.

NR 811.858(3)(3) Discharge to sanitary sewer. Discharge to sanitary sewer may be approved on a case-by-case basis if a study or experience has shown that problems will not occur in the sewage collection system or at the wastewater treatment plant. The discharge of lime softening sludge shall meet the requirements under s. NR 811.85 (1) (a). A water system owner shall submit plans to both the department’s wastewater section and public water engineering section for a new discharge or an increase in volume or percent solids of lime softening sludge to sanitary sewer for review and approval prior to initiation of the construction or operational change.

NR 811.858(4)(4) Mechanical dewatering. Mechanical dewatering may be utilized if approved by the department after review of the results of pilot testing. Supernatant from mechanical dewatering shall be discharged to a sanitary sewer, water of the state, or holding tank, pursuant to the applicable requirements under s. NR 811.85 (1). Effluent that is discharged to a surface water shall also meet the treatment requirements under s. NR 811.857 (3).

NR 811.858 HistoryHistory: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; CR 22-074: am. (intro.), (1) (b), (d), (f), cr. (1) (g), (h), am. (2), (3), r. and recr. (4) Register January 2024 No. 817, eff. 2-1-24.

NR 811.859(1)(1) General. The department may require special handling and disposal for spent media from water treatment plants under any of the following circumstances:

NR 811.859(1)(b)(b) Filter sand, green sand, ion exchange media, membranes, support media, and other media that may retain radionuclide material shall be evaluated when treating water with radium-226, radium-228, or uranium.

NR 811.859(2)(2) Disposal approval. The water system owner shall contact the department for approval prior to disposal of the medias listed under sub. (1). The water system owner shall submit a written request indicating the type of media, the volume of media, the contaminants of concern and their concentration in the influent water and the media, the proposed method of transportation, and the proposed method of disposal. A landfill that accepts spent media from a water treatment facility that treated groundwater containing radium shall comply with the requirements under s. NR 506.12 prior to accepting the spent media waste for disposal.

NR 811.859 HistoryHistory: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; CR 22-074: am. (1) (intro.), (a), (2) Register January 2024 No. 817, eff. 2-1-24.

NR 811.860NR 811.860 Backwash wastewater from surface water treatment plants. Filter backwash wastewater from surface water treatment plants shall be disposed of by any of the following methods:

NR 811.860(1)(1) Recycling. Filter backwash wastewater may be returned to the inlet end of the plant in accordance with the requirements under s. NR 811.862. Membrane filtration plants may not recycle backwash wastewater unless the waste goes through coagulation and settling processes prior to being applied to the membranes. Membrane manufacturers may have specific feed water quality parameter requirements that could limit recycling. Chemical cleaning waste from membrane plants may not be recycled unless specifically approved by the department. A plant recycling filter wastewater shall have an alternative means of disposing of wastewater available during periods when raw water quality precludes the ability to recycle all or some of the backwash water.

NR 811.860(2)(2) Discharge to sanitary sewer. Backwash water may be discharged to a sanitary sewer system subject to the requirements under s. NR 811.85 (1) (a).

NR 811.860(3)(3) Discharge to surface water. Backwash wastewater from filtration for surface water treatment may be discharged to a surface water of the state subject to the requirements under s. NR 811.85 (1) (b) and all of the following requirements:

NR 811.860(3)(a)(a) Suspended solids shall be removed from the filter backwash wastewater prior to surface water discharge. This will require settling and may require coagulation as determined by the department on a case-by-case basis. Additional treatment may be necessary to meet the requirements of the WPDES permit.

NR 811.860(3)(b)(b) The solids removed during treatment of backwash water shall be land spread or discharged to a holding tank in accordance with the requirements under s. NR 811.85 (1) (b) and (c).

NR 811.860(4)(4) Treated by secondary membrane. The filter backwash water may be treated by a dedicated membrane system and sent to the clearwell if approved by the department in accordance with all of the following requirements:

NR 811.860(4)(a)(a) The membrane, as can be demonstrated by integrity testing conducted every 8 hours, shall provide a minimum 99.9997 percent (5.5-log) removal of Cryptosporidium.