Efficiency of KrCl excilamp (222 nm) for inactivation of bacteria in suspension.
OBJECTIVE
To examine the killing efficiency of UV KrCl excilamp against gram-positive and gram-negative bacteria.


RESULTS
Vegetative cells of Bacillus cereus, Bacillus subtilis, Escherichia coli O157:H7, Staphylococcus aureus and Streptococcus pyogenes at initial populations from 10(2) to 10(7) colony-forming units (CFU) ml(-1) were treated by KrCl excilamp in sterile Ringer's solution with and without H(2)O(2). The number of viable cells was determined using spread plating techniques and nutrient agar method with subsequent incubation at 28 degrees C or 37 degrees C for 24 h. At estimated populations of 10(2)-10(5) CFU ml(-1) E. coli O157:H7 and Staph. aureus were the most sensitive and showed 100% disinfection within 15 s (29.2 mJ cm(-2)). Bacillus subtilis was more sensitive to UV treatment than B. cereus. The UV/H(2)O(2) inactivation rate coefficients within this population range were two times higher than those observed for UV treatment alone. No effect of H(2)O(2) was observed at 10(7) CFU ml(-1) for Bacillus sp. and Strep. pyogenes.


CONCLUSIONS
The narrow-band UV radiation at 222 nm was effective in the rapid disinfection of bacteria in aqueous suspensions.


CONCLUSIONS
KrCl excilamps represent UV sources which can be applied for disinfection of drinking water in advanced oxidation processes.
Matafonova
G G
GG
Baikal Institute of Nature Management, Siberian Branch of Russian Academy of Sciences, Ulan-Ude, Russia. ngal@binm.bscnet.ru
Batoev
V B
VB
Astakhova
S A
SA
Gómez
M
M
Christofi
N
N
D001419:Bacteria / Q000187:drug effects / Q000528:radiation effects*; D004202:Disinfectants / Q000494:pharmacology; D004203:Disinfection / Q000379:methods*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D054018:Lasers, Excimer; D050296:Microbial Viability / Q000187:drug effects / Q000528:radiation effects*; D014466:Ultraviolet Rays
D004202:Disinfectants; D006861:Hydrogen Peroxide