The UV dose-response behavior of laboratory cultures of waterborne bacteria were examined for UV doses ranging from ca. 0 -100 mW•s/cm2 using a collimated-beam reactor. Specific physiological responses measured in these tests included viability (ability to reproduce) and respiration (oxygen uptake rate). The results of these exposures indicated that resistance to UV-imposed loss of viability in E. coli cultures can be partially attributed to agglomeration during the irradiation process. From these results, it is conjectured that a bacterial population may be comprised of two sub-populations: one with low resistance (discrete or paired cells) and a second with high resistance (bacterial aggregates). A small fraction of the high-resistance portion of the population appears to be essentially unaffected by UV irradiation, thereby causing a discontinuity in the measured dose-response behavior. Moreover, the dose-response behavior of the highly resistant fraction is variable and difficult to describe quantitatively. The basis of these statements and most information in the literature is microbial viability as quantified by the membrane filtration assay. In contrast to these findings, the results of analyses for bacterial activity (respiration) suggest that comparatively little change in the population can be found to result from UV irradiation. This suggests that UV radiation accomplishes inactivation of the bacteria, but does not “kill” the bacterial cells per se, thereby highlighting the importance of considering bacterial repair processes in the design of UV disinfection systems.
Skip Nav Destination
Article navigation
Research Article|
May 01 2001
Bacterial responses to ultraviolet irradiation
E. R. Blatchley, III;
E. R. Blatchley, III
1Environmental and Hydraulic Engineering Group, School of Civil Engineering, Purdue University, West Lafayette, IN 47907-1284 USA
Search for other works by this author on:
N. Dumoutier;
N. Dumoutier
2CIRSEE, Lyonnaise des Eaux, 38 Rue du Président Wilson, 78230 Le Pecq, France
Search for other works by this author on:
T. N. Halaby;
T. N. Halaby
1Environmental and Hydraulic Engineering Group, School of Civil Engineering, Purdue University, West Lafayette, IN 47907-1284 USA
Search for other works by this author on:
Y. Levi;
Y. Levi
3Université Paris Sud, Faculté de Pharmacie, Laboratoire Sante Publique - Environnement, 5 Rue J.B. Clément, 92296 Chatenay-Malabry Cedex, France
Search for other works by this author on:
J. M. Laîne
J. M. Laîne
2CIRSEE, Lyonnaise des Eaux, 38 Rue du Président Wilson, 78230 Le Pecq, France
Search for other works by this author on:
Water Sci Technol (2001) 43 (10): 179–186.
Citation
E. R. Blatchley, N. Dumoutier, T. N. Halaby, Y. Levi, J. M. Laîne; Bacterial responses to ultraviolet irradiation. Water Sci Technol 1 May 2001; 43 (10): 179–186. doi: https://doi.org/10.2166/wst.2001.0614
Download citation file:
Sign in
Don't already have an account? Register
Client Account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.
eBook
Pay-Per-View Access
$38.00