Inactivation of Clostridium perfringens, total coliforms, and Escherichia coli by UV/H2O2 in wastewater treatment plant effluent

Abstract

This study evaluated the effectiveness of H2O2, UV radiation, and H2O2/UV processes to inactivate total coliforms, Escherichia coli, and Clostridium perfringens bacteria present in a treated sewage. The samples were collected at Samambaia Waste Water Treatment Plant in Campinas, Brazil. The photochemical assays were carried out using 125–3,640 mJ cm−2 doses of UV radiation. The initial H2O2 concentration was 30 mg L −1. The bacteria were quantified in samples of 100% raw effluent, which had an average of 1.1  106 most probable number (MPN)/100 mL of total coliforms, 2.3  105 MPN/100 mL of E. coli, and 1.4  104 MPN/100 mL of C. perfringens after treatment with activated sludge. Peroxidation did not efficiently inactivate the measured bacteria. The UV process incurred 5-log inactivation for total coliforms and E. coli bacteria, whereas advanced oxidation processes (AOPs) inactivated both bacteria. UV radiation and AOP incurred a 2-log inactivation of C. perfringens