Resumo

PANTOJA-ESPINOZA, J.C. et al. Comparative efficiencies of coliform bacteria inactivation in municipal wastewater by photolysis (UV) and photocatalysis (UV/TiO₂/SiO₂). Case: treatment wastewater plant of Salamanca, Spain. Rev. Mex. Ing. Quím [online]. 2015, vol.14, n.1, pp.119-135. ISSN 1665-2738.

Photolysis (UV-C radiation) and heterogeneous photocatalysis (UV-C/TiO₂/SiO₂) were used to inactivate E. coli and total coliform bacteria in biologically treated municipal wastewater. A 50 L sample was used with a recirculation rate of 1000 L/h through a UV photo reactor for 150 min reaction time, at a constant temperature. Samples were taken at different time intervals from each experimental run, then the colony forming units were counted, and the inactivation kinetic reaction was determined in a 2x2 factorial design with co-variable and replicates. The inactivation rate constants for coliform bacteria obtained in both processes, photolysis and photocatalysis, showed total E. coli and total coliform bacteria inactivation in short reaction times. ANOVA (p < 0.05) showed a significant effect for the Advanced Oxidation Process, bacteria and the co-variable (initial colony forming units). Comparison of the bacteria inactivation constant rates in short treatment times, obtained by t-Student test, demonstrated that photolysis and heterogeneous photocatalysis showed a significant difference (p < 0.05), allowing both techniques to fulfill the Spanish regulations for E. coli.

Palavras-chave : ANOVA analysis; rate constant; photocatalysis; TiO₂/SiO₂; E. coli.