2O 2 heterogeneous photocatalytic inactivation of coliforms in municipal wastewater in a TiO 2/SiO 2 fixed bed reactor: a kinetic and statistical approach]]>

摘要

Escherichia coli ( E. coli ) and total coliforms (TC) present in biologically treated municipal wastewater were inactivated in samples from a wastewater treatment plant in Salamanca, Spain, through two advanced oxidation processes: UV-C/H~(2)O~(2)photolysis and UV-C/(TiO~(2)/SiO~(2))/H~(2)O~(2)heterogeneous photocatalysis. A stainless steel reactor and a 40-W lamp (254?nm) were used. A 2?×?3?×?2 factorial design with covariates and repeated measures was performed, with the factors: initial pH of the sample (6, 7.5 and 9) and dose of H~(2)O~(2)(0 and 0.5?mmol/L). The kinetic analysis showed a first order reaction for the E. coli and TC inactivation. The highest inactivation rate constants, 0.523?min_(?1)for E. coli and 0.337?min_(?1)for TC, obtained in this work, correspond to experiments performed by UV-C/(TiO~(2)/SiO~(2)) photocatalysis, with initial pH 6 and 0.5?mM of H~(2)O~(2)/L; under these conditions, the time of total inactivation of E. coli and TC microorganisms was 10 and 20?min, respectively. The analysis of covariance confirms that after three min of the experiment, all considered parameters are significant (p?