NR 811.51
NR 811.51 Fluoridation. Sodium fluoride, sodium fluorosilicate and fluorosilicic acid shall conform to the applicable NSF/ANSI Standard 60 and AWWA standards B701, B702, and B703 in effect at the time of use. Other fluoride compounds which may be available shall be approved by the department. The following specific requirements shall be met:
NR 811.51(1)
(1)
Fluoride chemical storage. Fluoride chemicals shall be stored in accordance with the following requirements:
NR 811.51(1)(a)
(a) Fluoride chemicals shall be isolated from other chemicals to prevent contamination.
NR 811.51(1)(b)
(b) Fluoride chemicals shall be stored in covered or unopened shipping containers and stored inside a building.
NR 811.51(1)(c)
(c) Unsealed storage units for fluorosilicic acid shall be vented to the atmosphere at a point outside the building. The vent piping shall terminate a minimum of 24 inches above grade with a down-turned U-bend. The vent pipe opening shall be covered with a 24-mesh corrosion resistant screen.
NR 811.51(2)
(2)
Fluoride Acid housing. Equipment for feeding fluoride in the acid form and unsealed acid storage containers shall be housed in accordance with the following requirements:
NR 811.51(2)(a)
(a) All chemical feed equipment, solution tanks, and acid containers shall be housed in a separate room within the pumphouse away from controls, electrical contacts, and other equipment subject to damage. Fluoride chemical feed installations shall be installed in a room separate from all other chemicals.
NR 811.51(2)(b)
(b) Unsealed acid storage units or solution tanks shall be vented to the outside in accordance with sub.
(1).
NR 811.51(2)(d)
(d) Entrance may be from inside the pumphouse but shall include a gasketed, sealed door to minimize the transfer of fumes outside the fluoride room.
NR 811.51(3)
(3)
Chemical feed installations. Chemical feed installations shall:
NR 811.51(3)(b)
(b) Provide scales, loss-of-weight recorders, liquid level indicators, or graduated feed drums for determining the amount of chemical applied. The method shall be accurate to within 5% of the average daily change in reading. A meter shall be provided on the water fill line to a fluoride saturator.
NR 811.51(3)(c)
(c) Not allow fluoride addition before lime-soda softening or ion exchange softening.
NR 811.51(3)(d)
(d) Provide feeders accurate to within 5% of any desired feed rate.
NR 811.51(3)(e)
(e) Be such that the point of application of fluorosilicic acid, if into a horizontal pipe, shall be in the lower half of the pipe with the chemical injection nozzle projecting upward into the pipe as required by s.
NR 811.39 (7) (f).
NR 811.51(3)(h)
(h) Provide soft water for fluoride saturator makeup water. A meter shall be provided on the water fill line to a fluoride saturator.
NR 811.51(4)
(4)
Secondary controls. Secondary control systems for automatically controlled fluoride chemical feed devices shall be provided as a means of reducing the possibility for overfeed; these may include flow or pressure switches or other equivalent devices.
NR 811.51(5)
(5)
Dust control. Dust control shall meet the following requirements
:
NR 811.51(5)(a)
(a) Provision shall be made for the transfer of dry fluoride compounds from shipping containers to storage bins or hoppers in such a way as to minimize the quantity of fluoride dust which may enter the room in which the equipment is installed. The enclosure shall be provided with an exhaust fan and dust filter which place the hopper under a negative pressure. Air exhausted from fluoride handling equipment shall discharge through a dust filter to the atmosphere outside of the building.
NR 811.51(5)(b)
(b) Provision shall be made for disposing of empty bags, drums, or barrels in a manner which will minimize exposure to fluoride dust. A floor drain shall be provided to facilitate the hosing of floors.
NR 811.51(6)
(6)
Protective equipment. Protective clothing, gloves, goggles or face shields and aspirator shall be provided.
NR 811.51(7)
(7)
Testing equipment. Equipment shall be provided for measuring the quantity of fluoride in the water using the analytical methods as specified in s.
NR 809.113 (1), Table A. When also feeding phosphates, the electrode method is required. The Alizarin Visual method may be approved only in special cases where the owner can allocate the extra time needed for testing.
NR 811.51(8)
(8)
Dilution equipment. Where dilution of the chemical solution is necessary, a graduated container and transfer pump shall be provided.
NR 811.51 History
History: CR 09-073: cr.
Register November 2010 No. 659, eff. 12-1-10;
CR 22-074: am. (1) (c), (2) (a), (3) (h) Register January 2024 No. 817, eff. 2-1-24. NR 811.52
NR 811.52 Iron and manganese control. Iron and manganese control refers solely to treatment processes designed specifically for this purpose. The treatment process used will depend upon the character of the raw water. The selection of treatment processes shall meet specific local conditions as determined by engineering investigations, including chemical analyses of representative samples of water to be treated. The department may require the operation of a pilot plant in accordance with s.
NR 811.44 in order to gather all information pertinent to the design. Consideration shall be given to adjusting the pH of the raw water to optimize the chemical reaction. The following requirements for specified treatment processes shall be met:
NR 811.52(1)
(1)
Removal by oxidation-detention-filtration or oxidation-filtration. NR 811.52(1)(a)
(a)
Oxidation. Oxidation may be by aeration, as indicated in s.
NR 811.45, or by chemical oxidation with chlorine, potassium permanganate, sodium permanganate, hydrous manganese oxides, ozone or chlorine dioxide.
NR 811.52(1)(b)1.1. A detention period of 0.5 to 3 hours, as determined by pilot studies, shall be provided following oxidation by aeration in order to insure that the oxidation reactions are as complete as possible. The detention period may be omitted or reduced where a pilot plant study indicates no need for detention or that a detention period less than 30 minutes will be adequate and department approval is obtained.
NR 811.52(1)(b)2.
2. The detention basin shall be designed as a holding tank with sufficient baffling to prevent short circuits. Sludge collection equipment is not required. The floor shall be sloped to facilitate cleaning. Detention basins shall meet all potable water reservoir standards as required by subch.
IX.
NR 811.52(1)(c)
(c) Sedimentation. Sedimentation basins shall be provided when treating water with high iron or manganese content or both and a significant volume of oxidized material will be created or where chemical coagulation is used to reduce the load on the filters. Provisions for sludge removal shall be made. Sedimentation basins shall meet all potable water reservoir standards as required by subch.
IX.
NR 811.52(1)(d)
(d) Rapid rate pressure filters. Use of rapid rate pressure filters as well as gravity filters may be considered for iron and manganese removal. Rapid rate pressure filters for iron and manganese shall meet the requirements under s.
NR 811.49.
NR 811.52(2)
(2)
Removal by lime processes. The removal of iron and manganese by lime processes shall meet the requirements in s.
NR 811.57.
NR 811.52(3)
(3)
Removal by manganese greensand type filtration. The removal of iron and manganese by greensand type filtration consisting of a continuous feed of potassium or sodium permanganate to the influent of a manganese greensand filter, is more applicable to the removal of iron plus manganese than to the removal of iron only because of economic considerations. As an alternate method, application of the potassium permanganate to the greensand on a “batch" basis may be installed when the department determines “batch" application is as effective as continuous feed. The following requirements apply:
NR 811.52(3)(a)
(a) The permanganate shall be applied as far ahead of the filter as practical.
NR 811.52(3)(b)
(b) Other oxidizing agents or processes, such as chlorination or aeration, may be used prior to the permanganate feed to reduce the cost of the chemical.
NR 811.52(3)(c)
(c) The normal filtration rate shall be 3 gallons per minute per square foot.
NR 811.52(3)(d)
(d) The normal backwash rate shall be 8 to 10 gallons per minute per square foot for manganese greensand media and 15 to 20 gallons per minute per square foot for manganese coated media. Lesser backwash rates may be used if justified to the department by filter vessel manufacturers or through pilot studies under s.
NR 811.44.
NR 811.52(3)(f)
(f) Sampling faucets shall be provided prior to application of permanganate, immediately ahead of filtration and at the filter outlet.
NR 811.52(4)
(4)
Removal by ion exchange. The removal of iron and manganese by ion exchange may not be used unless pilot plant studies have demonstrated that satisfactory removal efficiencies can be continuously provided. There may be no oxidation of the iron or manganese prior to the process.
NR 811.52(5)
(5)
Testing equipment. Testing equipment shall be provided for all plants. The equipment shall have the capacity to accurately measure the iron content to a minimum of 0.1 mg/l and the manganese content to a minimum of 0.05 mg/l.
NR 811.52 History
History: CR 09-073: cr.
Register November 2010 No. 659, eff. 12-1-10;
CR 22-074: renum. (1) (d) (intro.) to (1) (d) and am., r. (1) (d) 1. to 3., am. (3) (d) Register January 2024 No. 817, eff. 2-1-24. NR 811.53(1)(1)
General requirements. Organic compounds may be removed by a variety of processes. All process designs shall be based on information from a pilot study conducted in accordance with s.
NR 811.44 with the compounds to be removed unless the pilot study is waived by the department. Unless the department approves other requirements, the processes shall be designed to remove a minimum of 99% of the contaminant in question.
NR 811.53(2)
(2)
Packed tower aeration. Packed tower aeration units shall meet the following requirements:
NR 811.53(2)(a)
(a) General. Packed tower aeration, which is also known as air stripping, may be used for the removal of volatile organic chemicals, trihalomethanes, carbon dioxide, and radon.
NR 811.53(2)(b)
(b) Process design. The process design shall include determination of the Henry's Constant for each contaminant, the mass transfer coefficient, air pressure drop, and stripping factor. Justification shall be provided for the selected design parameters including the height and other dimensions of the unit, air to water ratio, packing specifications, packing depth, and surface loading rate.
NR 811.53(2)(b)1.a.
a. The pilot study shall evaluate a variety of loading rates and air to water ratios at the peak contaminant concentration. Special consideration shall be given to removal efficiencies when multiple contaminants occur.
NR 811.53(2)(b)1.b.
b. If there is adequate past performance data on the contaminant to be treated, including at the peak contaminant concentration, the department may approve the process design based on the appropriate calculations without pilot testing.
NR 811.53(2)(b)2.
2. The installation shall be designed to reduce contaminants to below the maximum contaminant level and to the lowest practical level.
NR 811.53(2)(b)3.
3. The packing material shall be NSF/ANSI Standard 61 approved for use in potable water in accordance with s.
NR 810.09 (5). The packing material shall be resistant to the aggressiveness of the water, dissolved gasses, any chemicals added to the water supply, and any cleaning materials.
NR 811.53(2)(b)4.
4. The packing tower shall be constructed of materials compatible with potable water including stainless steel, reinforced concrete, aluminum, reinforced fiberglass, or plastic. The tower construction materials shall be resistant to the aggressiveness of the water, dissolved gasses, any chemicals added to the water supply, and any cleaning materials. Towers constructed of light weight materials shall be provided with adequate support to prevent damage from wind.
NR 811.53(2)(b)5.
5. The ratio of the column diameter to the packing diameter shall be at least 7:1 for the pilot unit and at least 10:1 for the full scale tower. The type and size of the packing used in the full scale unit shall be the same as that used in the pilot unit.
NR 811.53(2)(b)6.
6. The blower shall be adequately sized to provide sufficient air to achieve the desired removal rates. The minimum volumetric air to water ratio at the maximum water flow rate shall be 25:1. The maximum air to water ratio shall not exceed 80:1.
NR 811.53(2)(b)7.
7. The design shall give consideration to potential fouling problems from calcium carbonate, iron and manganese precipitation, and from bacterial growth. Pretreatment shall be provided where necessary to prevent significant fouling. Disinfection capability shall be provided immediately before and after packed tower aeration.
NR 811.53(2)(b)8.
8. The effects of temperature shall be considered in the process design as a drop in water temperature can result in a drop in contaminant removal efficiency.
NR 811.53(2)(c)1.1. Water shall be distributed uniformly at the top of the tower using spray nozzles or orifice-type distributor trays that prevent short circuiting. For multi-point injection, a minimum of one injection point for every 30 square inches of tower cross-sectional area shall be installed.
NR 811.53(2)(c)2.
2. A mist eliminator shall be provided above the water distributor system.
NR 811.53(2)(c)3.
3. A side wiper redistribution ring shall be provided at least every 10 feet in order to prevent water channeling along the tower wall and short circuiting.
NR 811.53(2)(c)4.
4. Sample faucets shall be provided on the tower inlet and outlet piping.
NR 811.53(2)(c)5.
5. An outlet sump, if provided, shall be accessible for cleaning purposes and be equipped with a drain valve. The drain shall not be directly connected to a storm or sanitary sewer.
NR 811.53(2)(c)6.
6. A drain fitting shall be installed in the outlet piping to allow for the discharge of water and any chemicals used to clean the tower. The drain shall not be directly connected to a storm or sanitary sewer.
NR 811.53(2)(c)7.
7. The design shall prevent freezing of the inlet riser, tower, and the outlet piping when the unit is not operating.
NR 811.53(2)(c)8.
8. All buried piping shall be maintained under a positive pressure greater than the elevation of the ground surface.
NR 811.53(2)(c)10.
10. Consideration shall be given to installing a butterfly valve in the inlet piping to control the water flow rate and to minimize air entrainment.
NR 811.53(2)(c)12.
12. The inlet piping shall be supported separately from the tower's main structural support.
NR 811.53(2)(d)2.
2. The air inlet to the blower and the tower discharge vent shall be screened and provided with a downturned, hooded or mushroom cap that protects the screen from the entrance of extraneous matter including insects and birds, obnoxious fumes, all types of precipitation and condensation, and windborne debris or dust. The screens shall be constructed of 24-mesh corrosion resistant material and installed at a location least susceptible to vandalism or damage. The air inlet shall also be provided with a dust filter.
NR 811.53 Note
Note: It is recommended that a 4-mesh corrosion resistant screen be installed in front of the 24-mesh screen on the air inlet system.
NR 811.53(2)(d)3.
3. The blower shall be provided with a weather-proof motor, a tight housing, and an adequate foundation.
NR 811.53(2)(d)4.
4. An air flow meter or department approved alternative method for determining the air flow shall be installed on the air inlet piping.
NR 811.53(2)(d)5.
5. A positive air flow sensing device and a pressure gauge shall be installed on the air inlet line to the tower. If positive air flow is not detected, the device shall automatically shut down the water flow.
NR 811.53(2)(d)6.
6. A backup motor for the blower shall be readily available where the tower is used to maintain primary drinking water standards.
NR 811.53(2)(e)1.1. The tower shall be provided with a sufficient number of access ports with a minimum diameter of 24 inches to facilitate inspection, media replacement, media cleaning, and maintenance of the interior.
NR 811.53(2)(e)2.
2. A means shall be provided for cleaning the packing material should it become fouled.
NR 811.53(2)(e)3.
3. Any clearwell or reservoir constructed to receive water from a tower shall be constructed to meet the potable water reservoir requirements of s.
NR 811.64.
NR 811.53(2)(e)4.
4. The tower shall be designed and constructed so that it can be extended without major reconstruction.
NR 811.53(2)(e)5.
5. A means of bypassing the tower shall be provided unless the requirement is waived by the department because the water system has access to other water sources that can provide an average day supply of water at minimum.
NR 811.53(2)(e)6.
6. Disinfection application points shall be provided on the tower inlet and outlet piping.
