en Environmental Health, Sciences, and Engineering Environmental Health, Sciences, and Engineering پژوهشي Original Article <p dir="ltr" style="text-align: justify;"><span style="font-size:14px;"><span style="font-family: times new roman;"><strong>Background: </strong>Titanium dioxide (TiO₂)-mediated photocatalysis has been found to be an efficient method of water treatment and is capable of degrading a wide range of organic pollutants and microbial agents with high efficiency. The microorganism <em>Pseudomonas aeruginosa</em> is resistant to chemicals and UV irradiation. Bacteria which are resistant to UV-induced oxidative damage of the cell membrane are susceptible to photocatalytic technology. The main objective of this research was to examine the photocatalytic removal of <em>P. aeruginosa</em> upon UV irradiation in the presence of TiO₂ nanoparticles.<br> <strong>Methods: </strong>Polluted water samples were prepared by the addition of <em>P. aeruginosa</em> colonies into water, followed by contact with UV, TiO₂, or a combination of the two in separate stages. The effect of various parameters, including contact time, pH, and TiO₂ concentration, on reaction efficiency was examined.<br> <strong>Results: </strong>The highest efficiency of bacterial disinfection was achieved with UV irradiation in the presence of TiO₂ nanoparticles, with complete (100%) removal of <em>P. aeruginosa</em> observed upon irradiation for 60 min in the presence of 0.4 g/L TiO₂ under conditions of neutral pH.<br> <strong>Conclusions: </strong>The results of this study suggest that from a technical and economic perspective, the UV/TiO₂ process may be effectively applied for the disinfection of polluted water. This process could be considered a promising method of cleaning and purification, and applicable for water disinfection.</span></span></p> <p dir="ltr" style="text-align: justify;"></p> Advanced Oxidation Processes , (AOPs), Water Disinfection, Pseudomonas Aeruginosa, Titanium Dioxide, UV Irradiation, Pseudo-First Order Kinetics 28 33 http://jhehp.zums.ac.ir/browse.php?a_code=A-10-33-1&slc_lang=en&sid=1 Roya Alimoradzadeh r.alimoradzade@gmail.com 10031947532846009280 10031947532846009280 Yes Department of Environmental Health Engineering, School of Health, Zanjan University of Medical Sciences, Zanjan, Iran. Ali Assadi assadi@zums.ac.ir 10031947532846009281 10031947532846009281 No Department of Environmental Health Engineering, School of Health, Zanjan University of Medical Sciences, Zanjan, Iran. Fatemeh Afshar r.alimoradzade@gmail.com 10031947532846009282 10031947532846009282 No Department of Environmental Health Engineering, School of Health, Hamadan University of Medical Sciences, Hamadan, Iran. Ali Reza Rahmani r.alimoradzade@gmail.com 10031947532846009283 10031947532846009283 No Department of Environmental Health Engineering, School of Health, Hamadan University of Medical Sciences, Hamadan, Iran. Mohammad Reza Samarghandi r.alimoradzade@gmail.com 10031947532846009284 10031947532846009284 No Department of Environmental Health Engineering, School of Health, Hamadan University of Medical Sciences, Hamadan, Iran.