NR 811.58(3)(3) Split treatment. If approved by the department, a lime-soda water treatment plant may be designed using ‘split treatment’ in which raw water is blended with lime-treated water to partially stabilize the water. Treatment plants designed to utilize ‘split treatment’ shall contain facilities for further stabilization by other methods.

NR 811.58(4)(4) Alkali feed. An alkali feeder shall be provided for all ion exchange water softening plants to provide stable water unless the effluent water is shown to be non-corrosive. Other waters may also be corrosive and require pH adjustment. The chemical shall be adequately mixed and the point of application located such that any deposition in the piping is minimized. The piping shall be accessible for cleaning or replacement. Equipment for monitoring pH shall be provided.

NR 811.58(5)(5) Carbon dioxide reduction by aeration. The carbon dioxide content of an aggressive water may be reduced by aeration. Aeration devices shall conform to s. NR 811.45.

NR 811.58(6)(6) Other treatment. Other treatment for controlling corrosive waters by the use of sodium silicate and sodium bicarbonate may be used where necessary. Any proprietary compound shall receive the specific approval of the department before use. Chemical feeders shall comply with the requirements in subch. VI.

NR 811.59NR 811.59 Taste and odor control. Waterworks which are designed and constructed to provide taste and odor control shall comply with any requirements provided for the following applicable methods:

NR 811.59(1)(1) Chlorination. Chlorination is effective for the removal of some objectionable odors. Adequate concentration and contact time shall be provided to complete the chemical reactions involved. Excessive potential trihalomethane or other disinfection by-product production through this process shall be investigated by bench-scale testing prior to design.

NR 811.59(2)(2) Chlorine dioxide. Chlorine dioxide may be used in the treatment of any taste or odor which is treatable by an oxidizing compound. Provision shall be made for proper storage and handling of sodium chlorite to eliminate any danger of explosion.

NR 811.59(3)(a)(a) Powdered activated carbon may be added prior to coagulation to provide maximum contact time. Although facilities to allow the addition at several alternate points is recommended, in no case may carbon be added near the point of chlorine application.

NR 811.59(3)(c)(c) Continuous agitation or resuspension equipment shall be provided to keep the carbon from depositing in the mixing chamber/slurry storage tank.

NR 811.59(3)(e)(e) The required dosage of carbon in a water treatment plant depends upon the tastes and odors involved. Provisions shall be made for adding sufficient amounts to meet peak demands.

NR 811.59(3)(f)(f) Powdered activated carbon shall be handled as a potentially combustible material. It shall be stored in a building or compartment as nearly fireproof as possible. Other chemicals may not be stored in the same compartment. A separate room shall be provided for carbon feed installations. Carbon feeder rooms shall be equipped with explosion-proof electrical outlets, lights, and motors.

NR 811.59(5)(5) Copper sulphate and other copper compounds. Continuous or periodic treatment of water with copper compounds to kill algae or other growths shall be controlled to prevent a level in excess of 1.0 mg/l as copper in the plant effluent or distribution system. Provisions shall be made for uniform distribution of the chemical.

NR 811.59(7)(7) Potassium permanganate. The department may approve application of potassium permanganate if the treatment will be controlled to insure that no residual color will be present in the finished water.

NR 811.59(8)(8) Ozone. Ozonation may be used as a means of taste and odor control. Adequate contact time shall be provided to complete the chemical reactions involved. Ozone is generally more desirable for treating water with high threshold odors. Requirements for ozonation are contained in s. NR 811.54.

NR 811.59(9)(9) Other methods. Any other methods of taste and odor control may be allowed by the department only after laboratory or pilot plant tests or both.

NR 811.59(10)(10) Flexibility. Plants treating water known to have taste and odor problems shall be provided with equipment and multiple chemical addition points to provide several alternative control processes.

NR 811.60NR 811.60 Ultraviolet (UV) Light. Ultraviolet light technology is a primary disinfectant typically used for Cryptosporidium and Giardia lamblia inactivation of both surface water and groundwater supplies. The U.S. Environmental Protection Agency Ultraviolet Disinfection Guidance Manual, EPA 815-D-03-007 dated June 2003, which is incorporated by reference, shall be used as the basis for the validation, design, and operation of all ultraviolet light systems. Ultraviolet light disinfection systems shall meet the requirements of ANSI/NSF standard 55 Class A dated August 13, 2021, which is incorporated by reference. Water systems designed to provide ultraviolet light disinfection shall comply with all of the following:

NR 811.60 NoteNote: A copy of the U.S. Environmental Protection Agency Ultraviolet Disinfection Guidance Manual, EPA 815-D-03-007 dated June 2003 is available for inspection at the Legislative Reference Bureau and may be obtained for personal use from the U.S. Environmental Protection Agency, epa.gov. A copy of ANSI/NSF standard 55 Class A dated August 13, 2021 is available for inspection at the Legislative Reference Bureau and may be obtained for personal use from NSF International, nsf.org.

NR 811.60(1)(1) Treatment objectives. The target pathogen and the target log inactivation shall be used to identify the corresponding required UV dose.