Municipal UV Regulations
Municipal applications are ones which feed water to the public and must comply with applicable drinking water regulations. These can include an entire city's drinking water supply, a small community water supply, or possibly other small municipal off grid housing water systems. Within these groups the flow rates needing to be treated can range from 50 USGPM to 3 BGD (billion gallons per day) depending on the population and distribution. Ultraviolet equipment installed in municipal applications must have undergone third party testing in order to prove its performance. Depending on where the equipment is installed will determine which UV validation protocol must be followed. The validation protocol required will depend on the application and the regulation that that specific application must comply to. The most recognized UV validations protocols for municipal type applications are USEPA UVDGM 2006 (UV Disinfection Guidance Manual), ETV, the German protocol DVGW W294 and the Austrian protocol ÖNorm.
USEPA UVDGM 2006:
In November 2006, the EPA provided the final version of the UVDGM which summarizes the LT2 (Long Term Enhanced Surface Water Treatment Rule) rule requirements for validation testing and presents the EPA's recommended validation protocol. This protocol provides guidance for how to conduct a UV system validation test. This document also gives alternative methods of testing outlining various validation protocols including DVGW W294, ÖNorm, and the NSF 55 Class A protocol. Please keep in mind that the differences between the NSF 55 Class A and the UVDGM suggest that the NSF 55 would not meet the LT2 rule.
Testing under this protocol should produce data for the UV equipment in question demonstrating its performance under specific flow rates and UV transmittance levels (performance being UV dose delivery). The dose delivery then indicates the Cryptosporidium log credits that the equipment can claim. All data is included in a validation report that has been signed off on by a third party expert.
The ETV validation protocol is one that can be described as an independent validation of the claims made about the performance of the environmental benefits of an innovative technology. This program offers not a label of a specific validation by a statement of verification of the equipment for use in business-to-business relations. ETV can be used to prove compliance with any relevant legislation or it can be used to convince others of performance claims, like regulators or potential customers of a certain technology. How ETV works is a four step process:
- STEP 1: Proposal phase - the technology is explained and any existing test data is examined at this time as well as the initial claims that have been made for this product
- STEP 2: Specific protocol preparation phase - the protocol that the manufacturer wishes to follow is determined
- STEP 3: Assessment and verification phase - the testing of the equipment and gathering of results is carried out
- STEP 4: Publication phase - the data is published and signed off on by the third party expert
DVGW is a German standard for products that come into contact with drinking water. This standard is similar to the NSF 55 standard with some significant differences. Under the DVGW standard the equipment being tested must comply with the rigors of the protocol which include a specific dose delivery of 40 mJ/cm² as well as stringent design specifications of the system's UV sensor.
DVGW's web link is http://www.dvgw.de/english-pages/dvgw/
ÖNorm is a German standard for products that come into contact with drinking water. This standard is similar to the NSF 55 standard with some significant differences. Under the ÖNorm standard the equipment being tested must comply with the rigors of the protocol which include a specific dose delivery of 40 mJ/cm² as well as stringent design specifications of the system's UV sensor.