Inactivation of environmental mycobacteria by free chlorine and UV

• Published in: Water research (Oxford) Vol. 44; no. 5; pp. 1329 - 1334
• Main Authors: Lee, Eun-Sook, Yoon, Tae-Ho, Lee, Mok-Young, Han, Sun-Hee, Ka, Jong-Ok
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.03.2010; Elsevier
• Subjects: Applied sciences; Beams (radiation); Buffers; Chlorine; Chlorine - pharmacology; Collimated-beam device; disinfection; Dose-Response Relationship, Radiation; drinking water; Drinking water and swimming-pool water. Desalination; Environmental Microbiology; Environmental mycobacteria; Escherichia coli; Escherichia coli - drug effects; Escherichia coli - radiation effects; Exact sciences and technology; Hydrogen-Ion Concentration - drug effects; Hydrogen-Ion Concentration - radiation effects; Inactivation; Irradiation; Kinetics; Low pressure; Medium pressure; microbial contamination; Microbial Viability - drug effects; Microbial Viability - radiation effects; Mycobacterium - drug effects; Mycobacterium - radiation effects; Mycobacterium avium; Mycobacterium fortuitum; Mycobacterium intracellulare; Mycobacterium lentiflavum; Other industrial wastes. Sewage sludge; Pollution; Saline; Ultraviolet; ultraviolet radiation; Ultraviolet Rays; Wastes; water treatment; Water treatment and pollution; Collimated-beam device; Medium pressure; Environmental mycobacteria; Ultraviolet; Chlorine; Low pressure; Phosphates; Drinking water treatment; Sensitivity analysis; Microbiology; Escherichia coli; Disinfection; Oxidant; Ultraviolet radiation; Pathogenic; Metabolic inactivation; Bacteria; Phosphorus compound; Biological contamination; Enterobacteriaceae
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2009.10.046

The resistance of environmental mycobacteria (EM) against chlorine and ultraviolet (UV) was evaluated for determination of the Ct value and UV dose to inactivate EM. Chlorine disinfection experiments were done on Mycobacterium fortuitum in oxidant demand-free buffered water at the worst condition (pH 8.5, 4 °C) and normal condition (pH 7.0, 20 °C). The Ct value for 3 log inactivation of M. fortuitum was 600 times greater than that of Escherichia coli. UV experiments were performed for various species of Mycobacterium avium, M. fortuitum, Mycobacterium intracellulare, and Mycobacterium lentiflavum. A UV collimated beam device was used for irradiation of four species suspended in phosphate buffered saline with doses of 5, 10, 20, 50, and 100 mJ/cm 2. UV sensitivity of mycobacteria was species-specific. More than 3 log of M. avium, M. intracellulare, and M. lentiflavum could be inactivated at 20 mJ/cm 2, whereas M. fortuitum was so resistant that 3 log inactivation required a dose of more than 50 mJ/cm 2. Mycobacteria were found 2–10 times more resistant to UV than E. coli for 3 log inactivation. There was no significant difference in the inactivation of mycobacteria with either low-pressure or medium-pressure UV irradiation.