AWWA WQTC60688

AWWA WQTC60688 Applying the USEPA UV Disinfection Guidance Manual: Validation and Operations of UV Systems
Conference Proceeding by American Water Works Association, 11/15/2004

Dinkloh, Ludwig

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Over the last decade, several countries in Europe started to accept the widespread useof ultraviolet (UV) systems for the disinfection of drinking water. The use ofUV technology for that particular application in the U.S. is still relatively small in comparison. Only over the last2 - 3 years has the focus of the North-American municipalities and designers shifted towards UVas an additive disinfection possibility.The most important precursor of the increased attention was the release of the US Environmental Protection Agency (USEPA) UVDisinfection Guidance Manual (UVDGM; 1st draft release in 06/2002 and 2nd draft release in06/2003). With the USEPA officially preparing theground of giving correctly sized UV systems inactivation credits for Cryptosporidium, Giardiaand virus, UV becomes available for US-American utilities as an important disinfection toolwith a series of benefits in regards to health and environmental friendliness.The UVDGM provides the requirements for a correctly sized UV system, the first of which is to undergo a validation process. This is required of every UV reactor model that a manufacturer wishes touse in the municipal drinking water market. Secondly, it needs to be operated within theboundaries of the successful validation.A big challenge to using UV in accordance to the UVDGM, is that a multitudeof UV dose rates (or better: Reduction Equivalent Doses = REDs) are acceptable, dependingon the actual target organism and log inactivation credit (project-specific sizing). Secondly, itdoes not specify one sole method to arrive at a specific UV dose but allows threepossibilities (validation-specific sizing). Finally, there are two approaches for arriving at acertain inactivation credit (validation/manufacturer-specific sizing).Overall, the possible variations and project-, customer- and manufacturer-specificrequirements lead to a very complex design scenario. Includes 14 references, tables, figures.