Assefa Alena¹, Omprakash Sahu^2,

In this study, the semiconductor photocatalytic disinfection of secondary treated municipal wastewater was investigated. Natural water from a spring in Ethiopia prefecture, which is used for the water supplies for the city of Ethiopia, Crete, and samples from the effluents of the secondary settling tank of the municipal wastewater treatment plant of Ethiopia were collected. The samples were exposed to UV-A irradiation in the presence of TiO₂. The parameters examined in this study were the length of TiO₂ / UV-A treatment for effective disinfection, the microorganism type (total coliforms, enterococci), the relative bactericidal activity of three different types of TiO₂, the amount of the catalyst needed, and the pH of the samples. The results presented here show that commercial TiO₂ powder Degussa P25 is the most effective catalyst of the three used. Enterococci showed a stronger resistance to photocatalytic disinfection, whereas small pH changes do not seem to have a significant effect on it.

semiconductor photocatalysis, water, wastewater, disinfection