Department of Chemical and Metallurgical Engineering, Faculty of Engineering and Built Environment, Tshwane University of Technology, Pretoria 0001, South Africa; Water Utilization Division, Department of Chemical Engineering, University of Pretoria, Pretoria 0002, South Africa
Nkhalambayausi-Chirwa, E.M., Water Utilization Division, Department of Chemical Engineering, University of Pretoria, Pretoria 0002, South Africa; Makgato, S.S., Department of Chemical and Metallurgical Engineering, Faculty of Engineering and Built Environment, Tshwane University of Technology, Pretoria 0001, South Africa
Process water from nuclear fuel recovery unit operations contains a variety of toxic organic compounds. The use of decontamination reagents such as CCl4 together with phenolic tar results in wastewater with a high content of chlorophenols. In this study, the extent of dehalogenation of toxic aromatic compounds was evaluated using a photolytic advanced oxidation process (AOP) followed by biodegradation in the second stage. A hard-to-degrade toxic pollutant, 4-chlorophenol (4-CP), was used to represent a variety of recalcitrant aromatic pollutants in effluent from the nuclear industry. A UV-assisted AOP/bioreactor system demonstrated a great potential in treatment of nuclear process wastewater and this was indicated by high removal efficiency (>98) under various 4-CP concentrations. Adding hydrogen peroxide (H 2 O 2) as a liquid catalyst further improved biodegradation rate but the effect was limited by the scavenging of OH radicals under high concentrations of H 2O2. Copyright © 2010 S. S. Makgato and E. M. Nkhalambayausi-Chirwa.