Wisconsin Administrative Code › Department of Natural Resources › NR 800 - Environmental Protection - Water Supply › Chapter NR 811 - Requirements For The Operation And Design Of Community Water Systems › Subchapter VII - Treatment › Section NR 811.50 - Filtration - membrane

Current through June 24, 2024
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:
(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.
(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.
(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.
Note:
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
.
(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).
(5) PRETREATMENT. Pretreatment shall be as
				  follows:
(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.
(b)
Reverse osmosis and
				  nanofiltration
. Pretreatment shall be provided where appropriate for
				  turbidity reduction, iron or manganese removal, stabilization of the water to
				  prevent scale formation, microbial control, chlorine removal for certain
				  membrane types, and pH adjustment. At a minimum, cartridge filters shall be
				  provided for the protection of the reverse osmosis or nanofiltration membranes
				  against particulate matter.