Rapid disinfection of E-Coliform contaminated water using WO₃ semiconductor catalyst by laser-induced photo-catalytic process

Abstract

Laser-induced photo-catalysis process using WO₃ semiconductor catalyst was applied for the study of disinfection effectiveness of E-coliform-contaminated water. For this purpose, wastewater polluted with E-coliform bacteria was exposed to 355 nm UV radiations generated by third harmonic of Nd: YAG laser in special glass cell with and without WO₃ catalyst. E-Coliform quantification was performed by direct plating method to obtain the efficiency of each disinfection treatment. The dependence of disinfection process on laser irradiation energy, amount of catalyst and duration of laser irradiation was also investigated. The disinfection with WO₃ was quite efficient inactivating E-coliforms. For inactivation of E-coliforms, less than 8 minutes' laser irradiation was required, so that, the treated water complies with the microbial standards for drinking water. This study opens the possibility of application of this simple method in rural areas of developing countries using solar radiation.

Keywords:

• Laser induced photo-catalysis
• water disinfection
• WO₃
• E-Coliforms
• wastewater treatment
• clean water supply
• laser applications
• heterogeneous photo-catalysis
• environmental applications

Acknowledgments

The support by King Fahd University of Petroleum and Minerals is gratefully acknowledged. The technical help by M. Rahman and M. N. Sayeed during this experiment is highly appreciated.