Section 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 determine special disposal requirements for sludge from plants treating water containing radium-226, radium-228, or uranium. These special 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 4 to 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) Multiple cells to provide flexibility in operation.

(e) Adjustable decanting devices.

(f) Means of convenient cleaning where appropriate.

(2)   Application to agricultural land. The department may allow liquid sludge to be applied to agricultural land by tank truck if the solids do not exceed 10 to 12% by weight. This method requires proper handling facilities, vehicles, and equipment to allow hauling and spreading which does not create a nuisance. Adequate sludge holding facilities are required for use during times that trucks cannot operate. Higher solids content sludges may also be spread. However, prior to increasing the solids content the local department sludge management specialist shall be contacted to evaluate the acceptability of spreading the high solids sludge. Land application of sludge, including the radium-226 content, shall comply with the applicable requirements of s. NR 204.07 .

(3)   Discharge to sanitary sewer. Discharge to sanitary sewer may be utilized if a study or experience has shown that problems will not occur in the sewage collection system or at the wastewater treatment plant. An equalization tank may be necessary to even out flows to the sewer system. The radionuclide content of the sludge shall comply with s. NR 811.856 .

(4)   Mechanical dewatering. Pilot testing of mechanical dewatering is necessary to show the results that may be obtained. The department shall review and approve proposals on a case-by-case basis to insure that water quality and effluent requirements will be met.

History: CR 09-073 : cr. Register November 2010 No. 659 , eff. 12-1-10.