Validation of ultraviolet (UV) reactors using Lagrangian Actinometry (LA) has been successfully
applied to several large-scale UV reactors for drinking water disinfection. The primary
advantage of LA is the ability of the method to yield a measurement of the UV-dose
distribution of the reactor. An accurate measurement of the UV dose distribution can be used
to provide an accurate prediction of reactor performance relative to any photochemical
endpoint for which accurate UV dose-response behavior is known.
In order to separate dyed microspheres (DMS) from background particles, it is
desired to provide DMS with larger sizes and higher fluorescence intensity. Three types of
microspheres with different diameters (nominally 5, 10 and 15 µm) and surface coating
materials were tested. The 10 and 15 µm DMS were better separated from background
particles in flow cytometry.
In this research, action spectra of three different types of DMS were also established.
The collimated MP source and bandpass optical filters used in these experiments allowed
measurement of wavelength-dependent dose-response behavior for all three DMS types over
the entire germicidal UV spectrum for UV doses in the range of 0-450 mJ/cm<sup>2</sup>. Internal
(microsphere) standards were applied for all samples to calibrate the measurements in flow
cytometry. The action spectra of three different types of DMS were similar and wavelengths
between 240 to 280 nm showed higher efficiency. A dose of 450 mJ/cm<sup>2>/sup> at the most sensitive
wavelength gave mean FI increases of 50, 700 and 400 units for 5, 10 and 15 µm DMS,
respectively. The 10 µm DMS provided the greatest sensitivity to UV radiation at all
wavelengths. The higher sensitivity of DMS can improve not only the separation from
background particles but also determination of dose distribution. Includes 6 references, table, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 920 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 10 |
| Published : | 11/01/2009 |
