Year

2019

Degree Name

Doctor of Philosophy

Department

School of Civil, Mining and Environmental Engineering

Abstract

This thesis systematically investigates the performance of a novel high retention (HR) – enzymatic membrane bioreactor (EMBR) for effective degradation of a broad spectrum of trace organic contaminants (TrOCs) commonly detected either in sewage-impacted water or in wastewater treatment plant effluent. In the last decade, laccase (EC 1.10.3.2), a copper-containing oxidoreductase enzyme, has been studied extensively for the degradation of recalcitrant pollutants. Laccase-catalysed degradation of TrOCs such as pharmaceuticals, pesticides, personal care products, industrial chemicals and steroid hormones has gained significant attention. These TrOCs occur ubiquitously in municipal wastewater and sewage-impacted water bodies. This can potentially be harmful to aquatic ecosystems and human health.

Initially, performance of laccase was assessed in batch enzymatic bioreactors due to the concern of enzyme washout in a continuous-flow treatment system. In an attempt to prevent enzyme washout, an enzymatic membrane bioreactor (EMBR) was developed by coupling an ultrafiltration (UF) membrane to an enzymatic bioreactor. Interestingly, during the operation of the EMBR, adsorption of some hydrophobic TrOCs (log D >3) onto the enzyme gel layer over the membrane surface resulted in enhanced degradation of the adsorbed compounds. This observation indicates the complementarity of simultaneous laccase and TrOC retention within EMBR. Hence, in this thesis, a novel high retention enzymatic membrane bioreactor (HREMBR) system was developed for enhanced TrOC degradation by coupling an enzymatic bioreactor with a high retention membrane separation process such as nanofiltration (NF) or membrane distillation (MD)...

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Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.