Photocatalytic disinfection of water polluted by Pseudomonas Aeruginosa

Photocatalysis by titanium dioxide (TiO2) is a water treatment method. Pseudomonas
aeruginosa is a microorganism resistant to chlorine and UV-C irradiation. TiO2 photocatalytic
technology can destroy bacteria, which are resistant to oxidative destruction of cell membrane
caused by sole UV irradiation. This study aims to investigate the total mineralization of the
bacterium (P. aeruginosa) to the extent of death and cell-mass destruction using TiO2
photocatalytic oxidation process. In this work the effects of parameters such as amount of
TiO2, irradiation time, initial concentration of bacterium, presence of ascorbic acid and effect
of cell wall on removal of P. aeruginosa were studied. The data, which were obtained in this
study, showed that the optimum concentration of TiO2 was 325 ppm. Also at the initial
concentration of TiO2 equal to 325 ppm and initial microorganism MPN / 100 ml equal to 300
and after 75 min UV irradiation time, P. aeruginosa removal efficiency was 94.3 %. Removal
efficiency of P. aeruginosa in the absence of TiO2 or UV irradiation was very low. Decreasing
the concentration of microorganisms increased its removal efficiency. Removal efficiency of
spheroplast cells was more than intact cells of P. aeruginosa, which shows the important role
of cell wall on cell resistance against chemical agents. Ascorbic acid had inhibitory effect on
this process.