Section NR 811.858 - Lime softening sludge Sludge from plants using lime to soften water will vary in quantity and in chemical characteristics depending on the softening process and the chemical characteristics of the water being softened. The department shall impose additional disposal requirements on a case-by-case basis for sludge from plants treating water containing radium-226, radium-228, uranium, or other radionuclides. These additional requirements shall modify the requirements for specific disposal methods. The requirements for specific disposal methods are as follows:
(1) LAGOONS. The design shall meet the following minimum requirements: (a) Locations free from flooding, with grading or ditching to divert surface runoff.(b) Minimum lagoon depth of 5 feet with interior and exterior slopes of 3:1.(c) Two years solids storage volume for temporary lagoons and 8- to 10-years storage volume for permanent lagoons.(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.(e) Adjustable decanting devices.(f) Means of convenient cleaning.(g) Lagoons shall be designed to comply with ch. NR 213.(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).(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). Note: 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.
(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.(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).Wis. Admin. Code Department of Natural Resources NR 811.858
CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10.Amended by, 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. 2/1/2024