AWWA WQTC62579

An assay based on application of dyed microspheres has been developed forcharacterization of process performance in photochemical reactors. Previous applications ofthese microspheres have involved reactor systems based on monochromatic lamp output at acharacteristic wavelength of 254 nm (i.e., low-pressure Hg lamps). Unlike low-pressure Hglamps, radiation from medium pressure lamps is not limited to 254 nm. Moreover, excimerlamps, which may deliver germicidal ultraviolet (UV) radiation other than 254 nm, represent a possible nonmercury-containing alternative UV source. To increase the generality of the application of dyedmicrosphere method, its performance in characterizing reactors delivering non-254 nm, orpolychromatic UV radiation has been tested. Wavelength-dependent UV dose-response behaviorof the dyed microspheres has been characterized using several different types of collimatedbeams. Collimators based on KrCl and XeBr excimer lamps have been used to deliver nearlymonochromatic radiation at 222 nm and 282 nm, respectively. Collimated UV radiation from amedium pressure mercury lamp was conditioned using narrow band-pass optical filters toexamine dose-response behavior more generally over the wavelength range 214 nm to 297 nm.The dose-response experiments conducted in this study, therefore, have provided theoretical andpractical preparation for flow-through experiments with dyed microspheres on UV systems withmedium pressure lamps and a prototype UV reactor that employs an excimer lamp. Includes 4 references, figure.

Product Details

Edition:

Vol. - No.

Published:

11/01/2005

Number of Pages:

10

File Size:

1 file , 830 KB