Required UV dose from EPA log-inactivation tables for Cryptosporidium, Giardia, and virus. Optional indicative reactor sizing based on flow and UV transmittance.
UV dose is independent of pH and temperature — unlike chlorine CT. The governing parameter is UV transmittance (UVT), which reflects how much 254 nm light the water absorbs. UV is the primary regulatory barrier for Cryptosporidium.
Dose Requirement
UV is not routinely credited for virus inactivation under UK/EPA rules. Values are MS2 surrogate — actual viruses vary significantly. Adenovirus requires substantially higher doses.
Reactor sizing is indicative only. All UV systems must be validated by the manufacturer using a third-party biodosimetry test against the specific water quality and flow conditions at your site.
m³/hr
%
Drinking water: typically 90–98%.
LP lamps: 254 nm, efficient, common for drinking water.