Simultaneous photocatalytic oxidation of pharmaceuticals and inactivation of Escherichia coli in wastewater treatment plant effluents with suspended and immobilised TiO2

Abstract

Simultaneous Escherichia coli inactivation and oxidation of pharmaceuticals in simulated wastewater treatment plant effluents has been investigated using a photocatalytic treatment with TiO2 in suspension and immobilised onto a fixed-bed reactor. Non-photocatalytic reference experiments of dark adsorption and photolysis showed a higher sensitivity of E. coli towards the chemical composition of water in comparison with the concentration of pharmaceuticals that remains unaffected. Moreover, it must be underlined that the presence of pharmaceuticals (including antibiotics) did not seem to affect the bacterial viability at such low concentrations. Concerning photocatalytic experiments, both suspended and immobilised TiO2 were able to simultaneously inactivate and oxidise both kinds of pollutants (bacteria and pharmaceuticals). The fixed-bed reactor showed similar activity to that of the slurry without deactivation after several cycles of reuse. That makes TiO2 photocatalysis a quite interesting technology for the treatment of drinking water supplies or wastewater plant effluents, allowing the removal of emerging contaminants such as pharmaceuticals during the disinfection treatment.