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Over the past two years Calgon Carbon has validated several large Ultraviolet (UV) Drinking WaterDisinfection Reactors at flow rates of 1 to 40 MGD at the UV validation facility in Portland,Oregon. The UV Reactors utilize medium pressure mercury arc lamps in a closed vessel withdiameters ranging from 18 inches to 48 inches.Validation involves the use of surrogate organisms, in this case MS2 Phage, that are added to thewater stream ahead of the UV reactor along with agents that decrease the UV transmittance ofthe water thereby simulating waters of different quality. Effluent samples are collected atdifferent operating conditions of UV Transmittance, Flow, Lamp power and Number of lamps.The reduction in viable organisms is used to obtain a UV Dose that can be correlated with thevarious operating parameters to generate operating curves for the reactor at a Water TreatmentPlant (WTP).The use of independently traceable process measurements, such UV Irradiance at each lamp, isused to ensure that the reactor is providing adequate removal of the target organism such asCryptosporidium, thus protecting public health.This paper discusses the design and validation as it pertains to the recently released draft US Environmental Protection AgencyUV Disinfection Guidance Manual (UVDGM). Several factors are described including themethodology used to obtain validation equations, the use of safety factors to cover any error invalidation and operation of reactors, and the ability to control the lamp power in a UV reactor toobtain the exact dose needed for the required disinfection credits. Includes 4 references, table, figures.

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Edition: Vol. - No. Published: 11/15/2004 Number of Pages: 17File Size: 1 file , 1.4 MB