NR 811.55(3)(a)(a) The designer of any proposed uranium removal equipment shall contact the department prior to the final design of the equipment to allow for department input on design requirements. The design shall be based on information obtained from department approved on-site pilot studies conducted on the water to be treated. The process design shall address the fate of uranium in the treatment process. Disposal of water treatment plant wastes containing uranium shall be in accordance with written department guidance. If applicable, disposal of treatment plant wastes containing uranium shall be to a sanitary sewer or wastewater treatment plant as approved by the department. The discharged water treatment plant wastes and spent media shall be analyzed for radionuclide content as required by the department. The disposal of spent media containing residual radionuclides shall be as approved by the department. NR 811.55(3)(b)(b) A minimum of 4 consecutive quarters of finished water sampling for uranium shall be required after the plant becomes operational to demonstrate treatment effectiveness. The sampling shall be conducted under worst case conditions. Uranium analyses shall be performed by a U.S. environmental protection agency approved laboratory. The laboratory shall forward a copy of the radiological analyses to the department in an electronic format. NR 811.55(3)(c)(c) Prior to constructing or operating the systems, the radiation protection section of the department of health services shall be contacted to obtain a radioactive material license to operate pilot and full scale installations when uranium will be concentrated on the resin or media to a level greater than 170 picocuries per gram at any time during use, including just prior to backwashing, regeneration, or disposal. NR 811.55(3)(d)(d) Disposal of uranium removal treatment plant waste shall comply with subch. XII. NR 811.56(1)(1) Sequestration by polyphosphates. Sequestration by polyphosphates is suitable when concentrations of iron, manganese, or a combination of both, are 1.0 mg/1, or less. Polyphosphate treatment may be less effective for sequestering manganese than for iron. The following requirements shall be met: NR 811.56(1)(a)(a) Where phosphate treatment is used, chlorine residuals shall be maintained in the distribution system. In addition: NR 811.56(1)(b)(b) Polyphosphates may not be applied ahead of iron and manganese removal treatment. The point of application shall be prior to any aeration or oxidation and as far upstream as practical from the chlorine or other oxidant application. NR 811.56(1)(c)(c) Chemical feed installations shall conform to the requirements of subch. VI. NR 811.56(1)(e)(e) Stock phosphate solution shall be kept covered and disinfected by carrying an approximate 10 mg/1 free chlorine residual unless the phosphate is not able to support bacterial growth, has a pH of 2 or less, and has not been diluted. NR 811.56(1)(g)(g) If polyphosphate sequestration is practiced, appropriate orthophosphate testing equipment shall be provided. NR 811.56(1)(h)(h) Possible adverse affects on corrosion shall be considered and addressed if necessary when phosphate addition is proposed for iron or manganese sequestering. NR 811.56(2)(2) Sequestration by sodium silicates. Sodium silicate sequestration of iron and manganese is appropriate only for groundwater supplies prior to air contact. Sodium silicate addition is applicable to waters containing up to 2 mg/l of iron, manganese, or a combination of both. The following requirements shall be met: NR 811.56(2)(a)(a) On-site pilot tests are required to determine the suitability of sodium silicate for the particular water and the minimum chemical feed rate needed. NR 811.56(2)(b)(b) Chlorine residuals shall be maintained throughout the distribution system to prevent biological breakdown of the sequestered iron. NR 811.56(2)(c)(c) Rapid oxidation of the metal ions such as by chlorine or chlorine dioxide shall accompany or closely precede the sodium silicate addition. Injection of sodium silicate more than 15 seconds after oxidation may cause detectable loss of chemical efficiency. Dilution of feed solutions much below 5% silica as SiO2 shall also be avoided for the same reason. NR 811.56(2)(d)(d) The amount of silicate added shall be limited to 20 mg/l as SiO2. The combined amount of added and naturally occurring silicate may not exceed 60 mg/l as SiO2. NR 811.56(2)(e)(e) Chemical feed installations shall conform to the requirements of subch. VI. NR 811.56(2)(f)(f) Sodium silicate may not be applied ahead of iron or manganese removal treatment. NR 811.57NR 811.57 Softening. The softening process selected shall be based upon the chemical qualities of the raw water, the desired finished water quality, the requirements for disposal of sludge or brine waste, the cost of plant and chemicals, and plant location. The applicability of the process chosen shall be demonstrated and discussed in detail in an engineering report. For very hard water, the sodium levels in cation exchange softened water shall be considered in selecting the treatment process. Following are requirements for specific processes: NR 811.57(1)(1) Lime-soda process. The applicable design standards for lime-soda softening of groundwater are the same as those for conventional clarification-filtration surface water treatment plants, except that the minimum settling time may be reduced to 2 hours. Where softening is included in the surface water treatment process, the clarification criteria shall govern. In addition: NR 811.57 NoteNote: See s. NR 811.47 for criteria pertaining to softening with solids contact units and s. NR 811.49 for filtration requirements. NR 811.57(1)(a)(a) Mechanical sludge removal equipment shall be provided in the sedimentation basin. NR 811.57(1)(b)(b) Determinations shall be made for the carbon dioxide content of the raw water. NR 811.57 NoteNote: When concentrations exceed 10 mg/l, the economics of removal by aeration as opposed to removal with lime should be considered. See s. NR 811.45 for aeration requirements.