title: Disinfection of urban wastewater by solar driven and UV lamp - TiO₂ photocatalysis: effect on a multi drug resistant Escherichia coli strain.
abstract: The effect of TiO₂ photocatalysis on the inactivation of an antibiotic resistant Escherichia coli strain selected from an urban wastewater treatment plant (UWWTP) effluent was investigated. Different light sources including a 250 W wide spectrum lamp, a 125 W UV-A lamp and solar radiation, as well as, photocatalysts loadings (TiO₂ Degussa P25) in the range from 0.05 to 2.00 g TiO₂ L(-1) were evaluated. The higher efficiency (total bacterial inactivation after 10 min of irradiation) was observed in the absence of TiO₂ when the wastewater was irradiated using the 250 W lamp. In the presence of TiO₂ a decreasing inactivation trend was observed (99.76% and 72.22% inactivation after 10 min irradiation at 0.10 and 2.00 g TiO₂ L(-1) respectively). Under solar simulated conditions the highest inactivation efficiency (93.17%) after 10 min of irradiation was achieved at the lower photocatalyst loading (0.05 g TiO₂ L(-1)). The concept of "reactor optical thickness" was introduced to explain the rates of disinfection observed. The optimum photocatalyst loading estimated by radiation absorption-scattering modeling was found to be 0.1 g TiO₂ L(-1) for all lamps. The difference between experimental tests and modeling may be due to TiO₂ particles aggregation. Comparative kinetic tests between solar and solar simulated photocatalytic (SSP) processes using 0.05 g TiO₂ L(-1) in suspension showed a quite similar inactivation behavior up to 30 min of irradiation, but only the SSP process resulted in a total inactivation of bacteria after 60 min of exposure. Antibiotic resistant test (Kirby-Bauer) on survived colonies showed that the SSP and SP processes affected in different ways the resistance of E. coli strain to the target antibiotics.
authors: Department of Civil Engineering, University of Salerno, via Giovanni Paolo II, 1, 84084 Fisciano, SA, Italy. Electronic address: l.rizzo@unisa.it.
authors: L
authors: L
authors: Rizzo
authors: Department of Civil Engineering, University of Salerno, via Giovanni Paolo II, 1, 84084 Fisciano, SA, Italy.
authors: A
authors: A
authors: Della Sala
authors: Department of Civil Engineering, University of Salerno, via Giovanni Paolo II, 1, 84084 Fisciano, SA, Italy.
authors: A
authors: A
authors: Fiorentino
authors: Environmental Nanocatalysis & Photoreaction Engineering, Department of Chemical Engineering, Loughborough University, Loughborough LE11 3TU, United Kingdom.
authors: G
authors: G
authors: Li Puma
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D004203:Disinfection / Q000379:methods*; D018432:Drug Resistance, Multiple; D004926:Escherichia coli / Q000187:drug effects / Q000528:radiation effects*; D010782:Photolysis; D013472:Sunlight; D014025:Titanium / Q000737:chemistry*; D014466:Ultraviolet Rays; D062065:Wastewater / Q000382:microbiology*; D014871:Water Microbiology
chemical_list: D000900:Anti-Bacterial Agents; D014025:Titanium; D062065:Wastewater; C009495:titanium dioxide
keywords: Antibiotic resistant bacteria; Indigenous E. coli strain; Kirby–Bauer method; Radiation absorption-scattering modeling; Solar photocatalysis