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 811.60 - Ultraviolet (UV) Light

Current through June 24, 2024
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:
Note:
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.
(1) TREATMENT OBJECTIVES. The target pathogen
				  and the target log inactivation shall be used to identify the corresponding
				  required UV dose.
(2) WATER QUALITY
				  CONSIDERATIONS AND PRETREATMENT. In order to provide adequate disinfection
				  treatment, some water sources may need treatment prior to ultraviolet light
				  disinfection. UV disinfection of surface water sources shall follow filtration.
				  Department approval for specific pretreatment requirements is required if any
				  of the parameters in Table No. 3 are exceeded in the water to be treated by
				  ultraviolet light.
Table No.
								  3
Inlet Water Quality
								  Parameters
Parameter
Maximum or Range
UV 254 mm Absorption
0.155 cm-1
Dissolved Iron
0.3 mg/l
Dissolved Manganese
0.05 mg/l
Hardness
120 mg/l
Hydrogen Sulfide
Non-detectable odor
Fouling Microorganisms
None
pH
6.5 to 9.5
Suspended Solids
10 mg/l
Turbidity
1.0 NTU
Total Coliform
1,000/100 ML
(3)
				  VALIDATION. Ultraviolet light treatment devices shall be validated by a third
				  party entity in accordance with the U.S. Environmental Protection Agency
				  Ultraviolet Disinfection Guidance Manual EPA 815-D-03-007 dated June 2003 or
				  another validation standard as approved by the department. The final
				  installation shall be equivalent or more protective than the validation testing
				  installation.
Note:
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,
www.epa.gov
.
(4) MATERIALS. The ultraviolet light housing
				  shall be type 304 or type 316L stainless steel.
(5) DESIGN.
(a) The ultraviolet treatment device shall be
				  designed to provide a UV light dose of a minimum of 40 millijoules per square
				  centimeter (mJ/cm 2) and shall also deliver the target dose as prescribed by s.
				  NR
				  810.62 by operating within the validated operating
				  conditions for that particular unit.
(b) The ultraviolet treatment assemblies
				  shall be designed to allow visual observation, cleaning, and replacement of the
				  lamp, lamp sleeves, and sensor window or lens.
(c) All ultraviolet lamps shall be housed in
				  type 214 quartz sleeves.
(d) Where
				  in-situ cleaning of the lamp sleeves is proposed, the design shall protect the
				  potable water from cleaning solutions.
1. When
				  off-line chemical cleaning systems are used, the UV enclosure shall be removed
				  from service, drained, flushed with an NSF/ANSI Standard 60 certified solution,
				  drained, and rinsed before being placed back in service.
2. On-line systems that use wipers or brushes
				  may use chemical solutions provided they are NSF/ANSI Standard 60
				  certified.
(e) An
				  automatic shutdown valve shall be installed in the water supply line prior to
				  the ultraviolet treatment device. When power is not provided the valve shall be
				  in the closed position.
(f) The
				  inlet and outlet piping to the reactors shall assure that the UV dose delivery
				  is equal to or greater than the UV dose delivered during validation.
(g) The flow to each reactor shall be equally
				  distributed and metered.
(h) Valves
				  shall be provided to allow isolating and removing from service each UV
				  reactor.
(i) Reactors shall be
				  provided with air relief and pressure control valves per manufacturer
				  requirements.
(j) UV transmittance
				  (UVT) analyzers shall be provided if UVT is part of the dose monitoring
				  strategy.
(k) Sample taps shall be
				  provided downstream of each reactor.