Analysis of a Low Pressure UV reactor under Multiple Upstream Elbow Configurations using UV Sensitive Fluorescent Microspheres

Abstract

Upstream piping configuration has been known to impact the UV reactor validation using biodosimetry tests. However, the influence of upstream configuration on the UV dose distribution has not been experimentally investigated. This research was performed to evaluate the UV reactor dose distribution under multiple upstream configurations using UV sensitive fluorescent microspheres. The upstream hydraulics configurations included two kinds of 90- degree bends and one straight pipe configuration. Experimental tests were performed at 51 gpm flow rate, 91% UV transmittance (UVT) on a single lamp low-pressure high-output (LPHO) UV reactor. The UV irradiation kinetics of the photo-chemically active fluorescent microspheres was performed with bench-scale collimated beam experiments. The correlation with microspheres fluorescence intensity distribution to UV fluence distribution was achieved by a statistical process involving Bayesian and Markov chain Monte Carlo integration technique. The results of this study showed that the straight pipe configuration produced a shift in UV fluence distribution to a higher UV fluence range compared to the two elbow configurations. No significant difference was formed between the two elbow configurations. The fluorescent microspheres Bayesian method can serve as an additional test to the traditional biodosimetry for UV reactor validation by providing sensitivity in detecting design parameter change and added confidence in the results by providing unbiased UV dose behavior.