NR 811.49 HistoryHistory: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; renumbering of (1) (e) made under s. 13.92 (4) (b) 1., Stats., Register November 2010 No. 659; CR 22-074: am. (1) (b), (c), (f) 6. b., (j) 1., cr. (1) (k) 9. Register January 2024 No. 817, eff. 2-1-24.

NR 811.495NR 811.495 Filtration — pressure. A pressure filter may not be used in the filtration of surface water, polluted waters, or following lime-soda softening as provided under s. NR 811.57. A pressure filter shall meet all of the following requirements:

NR 811.495(1)(1) Number. At least 2 filter units or cells shall be provided. Provisions shall be made to meet the plant design capacity at the approved filtration rate with one filter out of service. If only 2 units or cells are provided, each shall be capable of meeting the plant design capacity, normally the projected maximum daily demand.

NR 811.495(2)(2) Rate of filtration. The rate of filtration shall not exceed 4 gallons per minute per square foot of filter area except when pilot testing under s. NR 811.44 or full-scale testing as approved by the department has demonstrated adequate contaminant removal rates at the higher filtration rates, as determined by the department.

NR 811.495(3)(3) Filter material. The filter media material shall meet the requirements under s. NR 811.49 (1) (f).

NR 811.495(4)(4) Design details. A filter shall be designed to provide for all of the following:

NR 811.495(4)(h)(h) An air release valve on the highest point of each filter cell. The discharge line from the relief valve shall be metal and terminate downward facing with a 24-mesh corrosion resistant screen, at least 24 inches above the floor.

NR 811.50NR 811.50 Filtration — membrane. Membrane technologies have a wide range of applications from the use of lower pressure membranes for removal of surface water contaminants such as Giardia Lamblia and Cryptosporidium to the use of reverse osmosis for desalination, inorganic compound removal, and radionuclide removal. The following specific requirements shall be met:

NR 811.50(1)(1) Treatment objectives. The selection of the specific membrane process shall be matched to the desired treatment objectives. The department shall be contacted to determine inactivation/removal credits for the specific membrane and treatment objective membranes to be used in treatment of surface water or groundwater under the direct influence of surface water.

NR 811.50(2)(2) Water quality considerations. A review of historical source raw water quality data, including turbidity or particle counts or both, seasonal changes, organic loading, microbial activity, and temperature differentials as well as other inorganic and physical parameters shall be conducted. The data shall be used to determine feasibility and cost of the system and the degree of pre-treatment. Design considerations and membrane selection at this phase shall also address the issue of target removal efficiencies and system recovery versus acceptable transmembrane pressure differentials. On surface water supplies, pre-screening or cartridge filtration may be required. The source water temperature shall be considered when establishing the design flux of the membrane under consideration and the number of treatment units to be installed. Seasonal variation of design flow rates may be based on documented lower demand during colder weather.

NR 811.50(3)(3) Pilot testing. Prior to initiating the design of a membrane treatment facility, pilot testing under s. NR 811.44 shall be conducted. The pilot plant study shall be designed to identify the best membrane to use, need for pre- treatment, type of post- treatment, cold and warm water flux, backwash optimization, chemical cleaning optimization, fouling potential, operating and transmembrane pressure, integrity testing procedures, bypass ratio, amount of reject water, system recovery, process efficiency, particulate or organism removal efficiencies, and other design and monitoring considerations, each when applicable. The duration of the pilot testing shall be 9 to 12 months for microfiltration and ultrafiltration and 2 to 7 months for reverse osmosis and nanofiltration. The pilot testing shall be operated for a minimum of 3 clean in-place cycles unless an alternate operation schedule is approved by the department. The general protocol and sampling schedule shall follow the U.S. Environmental Protection Agency Membrane Filtration Guidance Manual, EPA 815-R-06-009, November 2005 Table 6.2, which is incorporated by reference, unless the department approves an alternative sampling schedule.

NR 811.50 NoteNote: U.S. Environmental Protection Agency Membrane Filtration Guidance Manual, EPA 815-R-06-009 is the U.S. Environmental Protection Agency guidance for membrane filtration published on November 5, 2005. A copy of the U.S. Environmental Protection Agency standard is available for inspection at the Legislative Reference Bureau and may be obtained from the U.S. Environmental Protection Agency, https://www.epa.gov.

NR 811.50(4)(4) Challenge Testing. Membranes treating surface waters or groundwater under the direct influence of a surface water shall be challenge tested to establish a product specific maximum Cryptosporidium and Giardia Lamblia log removal credit. Challenge testing shall meet the requirements of s. NR 810.45 (2).

NR 811.50(5)(5) Pretreatment. Pretreatment shall be as follows:

NR 811.50(5)(a)(a) Microfiltration and ultrafiltration. Pretreatment shall be designed to remove suspended solids and large particulate matter. The pretreatment may consist of a screen or strainer with a 200 to 500 micron rating. Chemicals used for pretreatment shall be certified for compliance with ANSI/NSF Standard 60.