AWWA WQTC71607

The objective of this currently on-going Water Research Foundation-funded study is to develop an innovative laser-induced fluorescence (LIF)-based method to measure real time, three dimensional mixing behavior and hydrodynamics within ultraviolet (UV) reactors. Both pilot- and lab-scale UV reactors equipped with low-pressure UV lamps were constructed for the LIF system. Conservative tracer tests were performed using the lab-scale reactor with UV lamps off, in which 3D instantaneous distribution of fluorescent dye within the reactor was captured real time. The images were further analyzed to successfully visualize the structure of eddy in the UV reactor and quantitatively analyze dye distributions in UV reactors. Reactive tracer tests will be conducted using the lab-scale reactor in which tracer dye decayed in response to UV lights such that distribution of tracer dye within the reactor was quantitatively correlated with UV dose distribution within the reactor. Further experiments using the lab-scale reactor are currently being performed and experiments using a pilot-scale UV reactor will be performed. Preliminary validation of this novel method by comparing the results to dose delivery measured using biodosimetry performed with Bacillus subtilis will also be performed. The newly developed LIF technique is expected to provide a highly innovative and unique approach for UV reactor optimization and validation as well as greater insight into the performance of UV reactors. Includes 11 references, figures.