TECHNION – Israel Institute of Technology Faculty of Civil and Environmental Engineering
The Division of Environmental Engineering, Water and Agriculture Technion City, Haifa 32000, Israel
The laboratory of “Environmental microbiology” at Technion tested the CQM device for its ability to inactivate the human pathogen Legionella pneumophila.
Legionella bacterium is an opportunistic environmental pathogen frequently isolated from hot drinking water.
The main clinical manifestations of Legionella infection are acute pneumonia (called Legionnaires’ disease) and Pontiac fever (a milder non-pneumonic flue like syndrome). The bacterium is mainly isolated from domestic hot-water systems (Atlas et al., 1995), cooling tower (Wery et al., 2008), fountains (Hlady et al., 1993), and similar disseminators that tap into public water supply. Other natural sources of Legionella include freshwater ponds, creeks, oxidation ponds, etc. (Shelton et al., 2000). The first report on Legionella was published by Tatlock in 1944 (Tatlock 1944), later rediscovered by McDade during the outbreak among people attending a convention of the American Legion in Philadelphia (July, 1976) (McDade et al. 1977). Since then an extensive number of publications emerged on its distribution, identification, serogrouping, ecology, epidemiology, molecular biology and clinical aspects (Fliermans et al., 1981; Martinelli et al., 2000). Currently there are at least 50 Legionella species and approx. 70 serogroups known to us (Grattard et al., 2006). Examination of the international published literature on Legionella pneumophila serogroups prevalence around the globe reveals that widely held isolated tap water serogroup is Legionella pneumophila serogroup 1 (Helbig et al., 2002; Tateyama et al., 2002; Harrison et al., 2007; Mika et al., 2005; Yu et al., 2008). Specific reports from countries
around the Mediterranean Sea: Turkey, Greece, Croatia, Italy, France and Spain also point on Legionella pneumophila serogroup 1 as the drinking water most prevalent serogroup isolate (Polat et al., 2007; Alexiou- Daniel et al., 1996; Kuzman 1996; Boccia et al., 2005; Chiarini et al., 2008; Campese et al., 2007; Rivera et al., 2007).
The CQM device
CQM developed a device intended to inactivate Legionella bacterium, found and colonizing hot water systems, through a process called electrolysis. Under the device specifications, it produces free chlorine and possible other oxidants (ozone, etc.) that inactivate/kill bacteria in water at 40oC. There were several questions that experimentally had to be answered:
1) Is the device efficient in annihilating Legionella pneumophila in water at 40oC or less?
2) Does the device produce bromates at high level of bromides?
To answer these questions, 2 experiments were carried out through seeding of L. pneumophila at high concentration (107-108 CFU/ml) into the CQM device and followed for its potential inactivation as a function of time. L. pneumophila enumeration was performed at the different time intervals by Haifa Public Health