NR 811.48(9)(e)2. 2. Pre-treatment devices shall be installed as necessary if the feed water does not meet the water quality requirements designated for the tablet chlorinator. Any pre-treatment device shall be compatible for use in a potable water system and shall not be used unless approved by the department. A strainer-filter shall be installed on the feed water piping, if necessary.

NR 811.48(9)(e)3. 3. A check valve shall be installed on the feed water piping upstream of any treatment equipment, control valve, or solenoid valve.

NR 811.48(9)(e)4. 4. A solenoid valve shall be installed on the feed water piping to control the flow of water into the tablet chlorinator. The operation of the solenoid valve shall be controlled based upon float switches or sensors located in the solution tank.

NR 811.48(9)(e)5. 5. Erosion type tablet chlorinators shall be provided with a control valve capable of regulating the flow of water through the erosion cell. The submittal for review to the department for an erosion-type tablet chlorinator shall include the chlorine delivery rate versus flow rate curve for the specified model.

NR 811.48(9)(f) (f) Chemical feed pumps.

NR 811.48(9)(f)1. 1. The chemical feed pump shall be wired to operate in association with the well or service pump as required by s. NR 811.39 (4).

NR 811.48(9)(f)2. 2. A tablet chlorinator producing calcium hypochlorite solution shall use a chemical feed pump installed in compliance with s. NR 811.39 (2), or a centrifugal pump.

NR 811.48(9)(f)3. 3. Centrifugal pumps shall be sized to match or exceed the maximum head condition at the point of injection.

NR 811.48(9)(f)4. 4. Flow paced chemical feed pumps installed in compliance with s. NR 811.39 (2) or centrifugal pumps with variable speed motors shall be incorporated into the design if the flow rate of the water being treated may vary based upon automatic control of the well or service pump. The requirements of s. NR 811.39 (2) (d) shall be met.

NR 811.48(9)(g) (g) Chemical injection location.

NR 811.48(9)(g)1. 1. Tablet chlorinator chemical feed pumps shall discharge at locations and in a manner that complies with the installation requirements of s. NR 811.39 (2) (f).

NR 811.48(9)(g)2. 2. When a centrifugal pump will discharge at a point not under continuous positive pressure, the outlet piping between the centrifugal pump and the point of chemical injection shall be installed with a vertical pipe loop that will extend to a height that is a minimum of 12 inches above the top of the solution tank and the location of the chemical addition pipe connection with the water system piping. A vacuum relief valve shall be installed on the top of the pipe loop. As an alternative to the installation of a vertical pipe loop, an electrically operated shut-off valve on the outlet piping, wired to operate in series with the operation of the well or service pump motor and the chemical feed pump, may be installed.

NR 811.48(9)(h) (h) Centrifugal pump discharge piping. The outlet piping of a centrifugal pump shall also be provided with a check valve and a manually operated shut-off valve. These valves shall be installed upstream of any pipe loop or electrically operated shut-off valve as required by par. (g) 2.

NR 811.48(10) (10) Sodium chlorite for chlorine dioxide generation. Proposals for the storage and use of sodium chlorite shall be submitted to the department for approval. Department approval shall be obtained prior to the preparation of final plans and specifications. Provision shall be made for proper storage and handling of sodium chlorite to eliminate any danger of fire or explosion.

NR 811.48(10)(a) (a) Storage.

NR 811.48(10)(a)1. 1. Sodium chlorite shall be stored by itself in a separate room and preferably shall be stored in an outside building detached from the water treatment facility. Sodium chlorite shall be stored away from organic materials with which it could react violently.

NR 811.48(10)(a)2. 2. Storage structures shall be constructed of noncombustible materials.

NR 811.48(10)(a)3. 3. If the storage structure is located in an area where a fire may occur, water shall be available to keep the sodium chlorite area cool enough to prevent heat induced explosive decomposition of the sodium chlorite.

NR 811.48(10)(b) (b) Handling.

NR 811.48(10)(b)1. 1. Care shall be taken to prevent spillage of sodium chlorite.

NR 811.48(10)(b)2. 2. An emergency plan of operation shall be available for the clean up of any spillage.

NR 811.48(10)(b)3. 3. Storage drums containing sodium chlorite shall be thoroughly flushed and the waste shall be discharged to an acceptable location prior to recycling or disposal.

NR 811.48(10)(c) (c) Feeders.

NR 811.48(10)(c)1. 1. Chemical feed pumps shall meet the requirements of s. NR 811.39 (2).

NR 811.48(10)(c)2. 2. Tubing for conveying sodium chlorite or chlorine dioxide solutions shall be Type 1 PVC, polyethylene or materials recommended by the manufacturer.

NR 811.48(10)(c)3. 3. Chemical feeders may be installed in chlorine gas rooms if sufficient space is provided or in separate rooms meeting the requirements of subs. (5) and (6).

NR 811.48(10)(c)4. 4. Feed lines shall be installed in a manner to prevent formation of gas pockets and shall terminate at a point of positive pressure.

NR 811.48(10)(c)5. 5. Check valves shall be provided to prevent the backflow of chlorine into the sodium chlorite line.

NR 811.48 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; CR 22-074: am. (1) (a) 2. to 4., (b), (4) (title), (5) (title), r. (5) (e), am. (6) (b), (7) (a), r. and recr. (8) Register January 2024 No. 817, eff. 2-1-24.