%0 Journal Article
%T Performance Evaluation of AOP/Biological Hybrid System for Treatment of Recalcitrant Organic Compounds
%A Stanford S. Makgato
%A Evans M. Nkhalambayausi-Chirwa
%J International Journal of Chemical Engineering
%D 2010
%I Hindawi Publishing Corporation
%R 10.1155/2010/590169
%X Process water from nuclear fuel recovery unit operations contains a variety of toxic organic compounds. The use of decontamination reagents such as 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 ( %) under various 4-CP concentrations. Adding hydrogen peroxide ( ) as a liquid catalyst further improved biodegradation rate but the effect was limited by the scavenging of radicals under high concentrations of . 1. Introduction 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. Chlorophenols are compounds of serious environmental concern due to their toxic impacts and discharge from a wide range of industrial sources. A large number of chlorophenol derivatives are refractory in nature rendering them resistant to biological degradation. The recalcitrance of these compounds results from the carbon-hydrogen bond, which is cleaved with great difficulty [1]. Due to their stability, halogenated phenols tend to accumulate in higher-order organisms. In summary, a large component of nuclear waste contains organic waste consisting of alcohols and phenolics. Current treatment processes for the removal of halogenated organic compounds involve dehalogenation using salts followed by chemical oxidation of the unhalogenated form [2]. The chemical process results in the production of harmful byproducts that require further disposal [3]. Among the alternative methods to the chemical treatment processes are the biological processes using specialized species of chlorophenol degrading organisms, oxidative reaction using AOP and photocatalysis [4]. However, when used alone AOPs still produce harmful byproducts and may be energy intensive. Lately, more interest has been directed towards finding solutions that involve the use of cultures of microorganisms to treat contaminated sediments and water impacted by nuclear waste [5]. The biological technology is
%U http://www.hindawi.com/journals/ijce/2010/590169/