Décontamination Bactérienne des Eaux par Impulsions Electromagnétiques Ultra courtes – DEBACIEM

As water circulating in cooling towers is a major dissemination factor of Legionella via its vapor released in the environment, DEBACIEM is a simple way to kill such pathogens without chemicals. The most of experiments taking place in CERPEM and for safety reasons, it was decided to work initially on Escherichia coli, which has morphological and membrane aspects similar to Legionella. The tests with Legionella were performed by VERI, another partner of the consortium.

In a first step, a protocol of batch tests (i.e. on a non-circulating bacterial suspension) was conducted before flow tests, in order to know more about effects of nsPEF on bacteria due to a lack of bibliographic references, as we checked. This protocol applied to E. coli appears to be a convenient way to test nsPEF lethality in TAR physical conditions.

It was expected a better efficiency of nanosecond pulses compared to microseconds ones. As nanosecond high voltage generators are currently available, they were used to test this hypothesis, offering a new experimental field to the CERPEM laboratory, based on pulses amplitude, duration and frequency. Unfortunately, no clear effect was observed, in contradiction with an US publication. This will facilitate the industrial applications, as expensive generators appear unnecessary.

As the nsPEF appear with a limited efficiency, further researches will be mainly academic, involving other bacteria or pulse characteristics.

Scientific production since the beginning of the project was the subject of two internal publications (by DEBACIEM consortium). The first one Effect of nsPEF according to several experimental conditions for the decontamination of Escherichia coli and the second one Bacteria disinfection of water by nanosecond pulsed electric field. Two international articles have been accepted for publication.