Chapter NR 811

NR 811.39(4)(d) (d) Feeders shall be designed and controlled to provide chemical feed rates proportional to flow and for variable flow rates shall be paced by a water meter.

NR 811.39(4)(e) (e) Automatic chemical feed rate control in combination with residual analyzers which have alarms for critical values and SCADA system reporting or recording charts may be used.

NR 811.39(5) (5) Solution tanks. The requirements for solution tanks, in s. NR 811.40 on storage and handling apply.

NR 811.39(6) (6) Chemical use measurement. The determination of chemical usage when using chemical feeders shall meet all of the following requirements:

NR 811.39(6)(a) (a) Weighing scales shall be provided for weighing cylinders at all plants utilizing chlorine gas.

NR 811.39 Note Note: It is recommended that indicating and recording type scales be used.

NR 811.39(6)(b) (b) Weighing scales are required for liquid solution feed unless comparable means for determining usage is approved by the department.

NR 811.39(6)(c) (c) Weighing scales are required for volumetric dry chemical feeders.

NR 811.39(6)(d) (d) Weighing scales shall be accurate enough to measure increments of 0.5 percent of load.

NR 811.39(6)(e) (e) Graduated lines on chemical tanks shall be displayed in units of volume and be in maximum increments of 3 percent of tank capacity.

NR 811.39(6)(f) (f) Radar and sonic level sensors that are programmed to display in pounds of chemical and that are accurate enough to measure increments of 0.5 percent of load may be used to determine chemical use.

NR 811.39(7) (7) Feed lines. Feed lines shall meet the following requirements:

NR 811.39(7)(a) (a) Be as short as possible in length of run, of durable, corrosion resistant material, easily accessible throughout the entire length, protected against freezing, and readily cleanable.

NR 811.39(7)(b) (b) Slope upward from chemical source to feeder when conveying gases.

NR 811.39(7)(c) (c) Introduce corrosive chemicals in a manner to minimize potential for corrosion.

NR 811.39(7)(d) (d) Be designed consistent with scale-forming or solids-depositing properties of the water, chemical, solution, or mixture conveyed.

NR 811.39(7)(e) (e) Not carry chlorine gas under pressure beyond the chlorine feeder room.

NR 811.39(7)(f) (f) Include injection taps constructed of metal or SCH 80 PVC components and check valves. Removable injection quills shall be provided when application is into a pipe of adequate diameter. Injection quills installed in a horizontal section of pipe shall be installed up into the bottom half of the pipe.

NR 811.39(7)(g) (g) Be color coded in accordance with s. NR 811.28 (6).

NR 811.39(8) (8) Service and carrier water supply. Water used for dissolving dry chemicals, diluting liquid chemicals, operating chemical feeders or as carrier water to deliver chemicals to injection locations shall be from a safe, approved source with appropriate backflow prevention provided. The department may grant an exception in cases where the finished water quality will not be affected by addition of the chemical mixed with untreated water.

NR 811.39 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; CR 22-074: am. (2) (e) (intro.), r. (2) (e) 2., renum. (2) (e) 3. to (2) (e) 3. (intro.) and am., cr. (2) (e) 3. a. to e., am. (2) (f) 1., (3) (d), r. and recr. (6) (intro.), am. (6) (a) to (d), cr. (6) (e), (f), am. (7) (f) Register January 2024 No. 187, eff. 2-1-24.

NR 811.40 NR 811.40 Storage and handling. Specific requirements regarding storage and handling are provided in the sections covering the particular chemical. Storage and handling installations shall meet the following general requirements:

NR 811.40(1) (1) Storage facilities. Storage facilities shall meet the following requirements:

NR 811.40(1)(a) (a) Space shall be provided for at least 30 days of chemical supply, convenient and efficient handling, dry storage conditions, and a minimum of 1.5 truck loads storage volume where purchase is by truck load.

NR 811.40(1)(b) (b) Covered or unopened shipping containers shall be provided for storage unless the chemical is transferred into an approved covered storage unit. Solution tanks shall have overlapping or threaded covers that provide sanitary protection for the chemical being stored. Large tanks shall be covered and those with top access openings shall have either threaded covers or the openings shall be curbed and fitted with overlapping covers. Grommets, pipe seals, or other sanitary means shall be provided to create a sanitary seal where tubes, hoses, and pipes pass through the walls or covers of chemical storage tanks.

NR 811.40(1)(c) (c) Solution storage or day tanks supplying chemical feeders directly shall have at a minimum sufficient capacity for one day of operation. If the chemical solution is prepared from a powder or slurry, 2 solution tanks shall be required if necessary to assure continuity of feed.

NR 811.40(1)(cm) (cm) Graduated lines may not be used to determine daily chemical usage when the daily use is less than 5 percent of the tank capacity.

NR 811.40(1)(d) (d) Solution storage or day tanks supplying feeders directly shall have a maximum capacity such that daily chemical solution usage is a minimum of 5 percent of the tank capacity. The department may approve chemical container storage volumes that will allow daily chemical solution usage less than 5 percent of the tank capacity if supporting information is provided to the department and the chemical storage container is placed on a scale, or another department approved method is installed, to accurately determine daily chemical usage. Graduated lines shall not be used to determine daily chemical usage in cases when the daily use is less than 5 percent of the tank capacity. The maximum storage volume shall not exceed 45 days for sodium hypochlorite and 60 days for all other chemicals.

NR 811.40(1)(e) (e) Storage facilities shall be constructed of, or lined with, materials compatible with the chemical being handled.

NR 811.40(1)(f) (f) Mixing equipment shall be provided where necessary to assure a uniform chemical solution strength. Continuous mixing shall be provided to maintain slurries in suspension.

NR 811.40(1)(g) (g) Means shall be provided to accurately determine the amount of chemical applied in accordance with s. NR 811.39 (6).

NR 811.40(1)(h) (h) For non-bulk tanks, suction lines shall extend into the tank through the tank cover. Chemical feed pumps shall be installed at a height above the maximum liquid level in the chemical storage tank. Flooded suctions, for bulk tanks and if necessary to prevent loss of prime, may be approved by the department on a case-by-case basis.

NR 811.40(1)(i) (i) Adequate means of draining tanks shall be provided, but there may be no direct connection between any drain piping and a sanitary sewer. Chemicals shall not be discharged directly to a storm sewer. Drain piping shall terminate at least 2 pipe diameters, but not less than 3 inches, above the overflow rim of a receiving sump, conduit or waste receptacle.

NR 811.40(1)(j) (j) Overflow pipes, if provided, shall be turned downward, provided with a 24-mesh corrosion resistant screen, have a free air break discharge, and be located in a conspicuous location.

NR 811.40(1)(k) (k) If subsurface locations for solution or storage tanks are approved by the department, the tanks shall be free from sources of possible contamination and located to assure positive drainage for groundwater, accumulated water, chemical spills, and overflows.

NR 811.40(1)(L) (L) Chemicals shall be stored in accordance with the following requirements:

NR 811.40(1)(L)1. 1. Each chemical shall be provided with its own secondary leakage containment.

NR 811.40(1)(L)2. 2. Each of the following chemicals shall be stored in a separate room with no other chemicals:

NR 811.40(1)(L)2.a. a. Fluoride.

NR 811.40(1)(L)2.b. b. Ammonia.

NR 811.40(1)(L)2.c. c. Powders.

NR 811.40(1)(L)2.d. d. Gases.

NR 811.40(1)(m) (m) All buried chemical solution lines and gas lines shall be installed within protective conduit piping. Each chemical solution line shall be placed in its own protective conduit piping.

NR 811.40 Note Note: When the chemical feed equipment will not be installed near the point of chemical application it is recommended that chemical solution piping be installed within protective conduit from the chemical feed equipment to the point of chemical application.

NR 811.40(1)(n) (n) Gases from feeders, storage, and equipment exhausts shall be conveyed to the exterior of the building above grade and remote from air intakes to reduce the health and safety risk to operators and reduce corrosion of equipment and facilities from chemical vapors. Chemical vapor ventilation systems shall meet the following requirements as applicable:

NR 811.40(1)(n)1. 1. Fluoride and ammonia liquid storage tanks shall be vented to the exterior of the building but not through vents in common with day tanks.

NR 811.40(1)(n)2. 2. Chemical tank vents, when provided, shall be vented to the exterior of the building and terminate downward facing with a 24-mesh corrosion resistant screen. The tank vent shall terminate as high as practical, but a minimum of 24 inches above surrounding grade.

NR 811.40(1)(o) (o) Permanent signs identifying the chemical for each fill tube shall be posted at chemical offloading areas. Permanent signs identifying the tank contents shall be posted adjacent to or on chemical storage tanks.

NR 811.40(1)(p) (p) Compliance with local, state, and federal safety codes, including department of safety and professional services and OSHA codes, for other applicable chemical safety and handling requirements is required.

NR 811.40(2) (2) Handling facilities. Handling facilities shall meet the following requirements:

NR 811.40(2)(a) (a) Equipment shall be provided for measuring quantities of chemicals used to prepare feed solutions.

NR 811.40(2)(b) (b) Piping for chemicals shall be compatible with the chemical being conveyed.

NR 811.40(2)(c) (c) The following equipment shall be provided for each installation where chemicals are handled:

NR 811.40(2)(c)1. 1. Where the eyes or body of any person may be exposed to injurious corrosive materials, suitable facilities for quick drenching or flushing of the eyes and body shall be provided as required in s. SPS 332.15.

NR 811.40(2)(c)2. 2. Rubber gloves, protective clothing, and safety goggles that form a tight seal with the face shall be provided for each operator who prepares chemical solutions.

NR 811.40(2)(c)3. 3. A dust respirator of the prescribed type shall be provided for handling dry chemicals if required in the respective material safety data sheet or s. SPS 332.15.

NR 811.40(2)(d) (d) Provision shall be made for the transfer of dry chemicals from shipping containers to storage bins or hoppers in such a way as to minimize the quantity of dust generated. Control shall be provided by use of one of the following:

NR 811.40(2)(d)1. 1. Vacuum pneumatic equipment or closed conveyor systems.

NR 811.40(2)(d)2. 2. Facilities for emptying shipping containers in special containers.

NR 811.40(2)(d)3. 3. Exhaust fans and dust filters which place the hoppers or bins under negative pressure.

NR 811.40(2)(e) (e) Carts, elevators, or other appropriate means shall be provided for lifting chemical containers to minimize lifting by operators.

NR 811.40(2)(f) (f) Electrical equipment shall be used which will prevent explosions, particularly when using sodium chlorite and activated carbon. Equipment shall comply with ch. SPS 316.

NR 811.40(2)(g) (g) Procedures for disposing of empty bags, drums, carboys, or barrels shall minimize exposure to dusts or chemicals.

NR 811.40(2)(h) (h) Acids shall be kept in closed, acid-resistant shipping containers, or storage units. Transfer from shipping containers to solution or day tanks shall be through acid resistant hose or pipe by means of a transfer pump.

NR 811.40(3) (3) Chemicals. All chemicals used to treat or produce potable water shall meet the following requirements:

NR 811.40(3)(a) (a) Shipping containers shall be fully labeled to include chemical name, purity, applicable NSF/ANSI standard approval in conformance with par. (b), concentration and supplier name and address.

NR 811.40(3)(b) (b) Chemicals shall meet the requirements of s. NR 810.09 (1).

NR 811.40 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; correction in (1) (p), (2) (c) 1., 3., (f) made under s. 13.92 (4) (b) 6., 7., Stats., Register December 2011 No. 672; CR 22-074: cr. (1) (cm), am. (1) (d), (g), (j), r. and recr. (1) (L), renum. (1) (n) to (1) (n) (intro.) and am., cr. (1) (n) 1., 2., Register January 2024 No. 817, eff. 2-1-24.

subch. VII of ch. NR 811 Subchapter VII — Treatment

NR 811.41 NR 811.41 General treatment design. The design of treatment processes and devices shall depend on evaluation of the nature and quality of the particular water to be treated and the desired quality of the finished water. Treatment shall be provided by each supplier of water if necessary in order to ensure that the finished water supplied to consumers meets the primary maximum contaminant levels contained in ch. NR 809 and is not objectionable to an appreciable number of consumers. The requirements of specific treatment processes are provided in ss. NR 811.42 to 811.60.

NR 811.41 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10.

NR 811.42 NR 811.42 Treatment of water from surface water sources. Treatment of water from surface water sources shall meet the following requirements:

NR 811.42(1) (1) General requirements. All public water supply systems drawing water from lakes, rivers, streams, or other surface water sources shall, after the water is drawn, treat the water as provided in this chapter. In general and at a minimum, this treatment shall include coagulation, sedimentation, and filtration plus disinfection or membrane filtration plus disinfection. Filtration is required in all cases. Total plant removal and inactivation shall provide a minimum 99.9 percent (3-log) inactivation of Cryptosporidium and Giardia Lamblia plus 99.99 percent (4-log) inactivation of viruses.

NR 811.42(2) (2) Treatment requirements. The following treatment requirements shall be met:

NR 811.42(2)(a) (a) Conventional plants consisting of coagulation, sedimentation, and filtration that meet the turbidity requirements in s. NR 810.29 (1) are granted the following removal credits: 99.7 percent (2.5-log) Giardia Lamblia, 99.9 percent (3.0-log) Cryptosporidium and 99 percent (2-log) virus. The remaining 68 percent (0.5-log) Giardia Lamblia inactivation and 99 percent (2.0-log) virus inactivation shall be provided by CT disinfection. For conventional plants, a minimum of one-half of the required CT shall be provided after filtration.

NR 811.42(2)(b) (b) Log removal credit for membrane filtration shall be site specific as approved by the department.

NR 811.42(2)(c) (c) Additional treatment may be required by the department as provided in s. NR 810.35.

NR 811.42(2)(d) (d) The department may approve any request for a deviation from required treatment methods based on data which shows that the requirements of this chapter are unnecessary in the specific case.

NR 811.42(3) (3) Redundancy. All critical treatment components shall be provided with redundancy.

NR 811.42(4) (4) CT values. CT values for the inactivation of Giardia Lamblia, Cryptosporidium, and viruses can be found in ss. NR 810.47 to 810.62.

NR 811.42(5) (5) Chlorine residual requirements. The free chlorine concentration in the water entering the distribution system shall be at least 0.2 mg/1 at the entry point to the distribution system and detectable throughout the distribution system or the total combined chlorine concentration shall be at least 1.0 mg/l at the entry point to the distribution system and detectable throughout the distribution system. Continuous chlorine residual monitoring of the water entering the distribution system shall be provided as required in ss. NR 809.74 (2) and 810.38 (2) (c).

NR 811.42 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10.

NR 811.43 NR 811.43 Treatment of water from groundwater sources. Treatment of water from groundwater sources shall meet the following requirements:

NR 811.43(1) (1) Disinfection capability required. All municipal water systems constructed or modified after December 1, 2010, shall have equipment and the necessary appurtenances that can continuously disinfect the water. The department may require the installation of disinfection equipment at existing other-than-municipal water systems if necessary to ensure a safe water supply.

NR 811.43(2) (2) Disinfectant residual requirements. Disinfection of water drawn from groundwater sources is to supplement and not replace proper well location, construction, and source protection. When disinfection of water drawn from a groundwater source is required to maintain bacteriologically safe water, the residual maintained in the distribution system and the residual monitoring is the same as that required for surface water in s. NR 811.42 (5).

NR 811.43(3) (3) Disinfection requirements for wells. Specific disinfection requirements for wells are provided in subch. II. Any additional disinfection requirements for wells will be developed by the department if necessary on a case by case basis.

NR 811.43(4) (4) Disinfection of groundwater exposed to the atmosphere as part of a treatment process. Disinfection of water drawn from groundwater sources is required at facilities that expose the water to the atmosphere, such as open basins, open filters, air stripping towers, or gravity aerators.

NR 811.43(5) (5) Required actions for wells with non-complying water quality. One of the following actions shall be taken after consulting with the department if untreated water drawn from a groundwater source exceeds one or more of the primary maximum contaminant levels in ch. NR 809 or a department health advisory:

NR 811.43(5)(a) (a) The well shall be removed from service and permanently abandoned.