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UV-ADVANCED OXIDATION TREATMENT OF MICROPOLLUTANTS IN SECONDARY WASTEWATERS by Jacque-Ann Natacia Grant A thesis submitted in conformity with the requirements for the degree of Doctor of Philosophy Graduate Department of Civil Engineering University of Toronto © Copyright by Jacque-Ann Natacia Grant (2015) ii UV-ADVANCED OXIDATION TREATMENT OF MICROPOLLUTANTS IN SECONDARY WASTEWATERS Jacque-Ann Natacia Grant Doctor of Philosophy Graduate Department of Civil Engineering University of Toronto 2015 Abstract Ultraviolet light+hydrogen peroxide (UV/H2O2) advanced oxidation is known to effectively oxidise micropollutants in wastewater. Its relatively high cost and energy requirements in comparison to other treatment options, however, have limited its implementation. This research evaluated the use of coagulation as a modification to the pre-tertiary component of the wastewater treatment process. The objective was to reduce the background scavenging capacity of the wastewater as a means of improving the oxidation efficiency of UV/H2O2 while reducing the cost and energy requirements. Effluent organic matter (EfOM) was identified as the primary wastewater component responsible for scavenging of the hydroxyl radicals required for oxidation in UV/H2O2 treatment. The organic constituents of EfOM that are the driving force for its reactivity with the hydroxyl radical were identified as the high molecular weight components (biopolymers) and tryptophan-protein like components. Since EfOM concentration and composition can vary from one water matrix to another, a comparison of secondary wastewaters from membrane bioreactor (MBR) and activated sludge (AS) treatment systems showed that the average scavenging capacity of the AS systems exceeded the average of the MBRs such that MBRs may be more amenable to UV/H2O2 treatment. iii Coagulation of the wastewater using ferric chloride, aluminium sulphate, and polyaluminium chloride primarily removed the high molecular weight components and significantly reduced the EfOM scavenging capacity. This improvement in wastewater quality also resulted in an improvement in the degradation rates of micropollutant compounds, reduced the energy requirements required to achieve 1-log removal of the compounds, and significantly reduced the costs associated with the UV/H2O2 system. No one coagulant outperformed any of the others; however the study demonstrated that coagulation is a feasible modification for a wastewater treatment plant upstream of an UV-AOP system. It was also found that the cost benefit to UV/H2O2 exceeded the chemical costs of coagulation. Nevertheless, facilities considering UV- AOP systems should weigh the benefits of increasing the H2O2 concentration or using coagulation as the cost savings are relatively similar at high H2O2 concentrations. iv Acknowledgments O taste and see that the Lord is good; blessed is the man that trusteth in Him. I thank Almighty God for His continual grace and strength throughout this project, for it is only in Him and through Him all things are possible. This project has received funding support from the Government of Ontario. Such support does not indicate endorsement by the Government of Ontario of the contents of this material. Financial support was also provided by the Ontario Research Fund through the Centre for the Control of Emerging Contaminants. I am deeply grateful to my thesis supervisor, Professor Ron Hofmann, for his support and guidance throughout the course of this work academically and professionally. I also thank Professor Robert Andrews and Hugh Monteith for being on my supervisory committee and the suggestions and feedback provided. I thank Sonya Kleywegt and David Poirier of the Ontario Ministry of Environment and Climate Change, Laura Meteer of the Regional Municipality of York, and Keith Bircher of Calgon Carbon Corporation for the support provided throughout this project. I am also grateful to Hydromantis Environmental Software Solutions Inc. (Hamilton, Ontario, Canada) for allowing the use of the proprietary CapDet Works software for the cost modelling analysis, to Dr. Monica Tudorancea and Dr. Sigrid Peldzsus (University of Waterloo) for performing LC-OCD analyses, to Dr. Viviane Yargeau and Rachel Benoit of Yargeau Laboratories (McGill University) for estrogenicity analyses, and Dr. Jim Bolton of Bolton Photosciences Inc. for the use of UVCalc 2B. I would also like to express my gratitude to Jim Wang, Hong Zhang, Russell de Souza, Ding Wang, Anwar Sadmani, Iolanda Montagnese, Montaseer Rahman, Min (Talia) Xu, Jiafan Yang, Clare Lin, and Elena Li for their assistance in the lab, and to my DWRG colleagues for their general encouragement along the way. Finally, I am grateful and thankful for my mom, Mary Elizabeth Grant, for her unwavering support, encouragement, and belief in me throughout this journey. v Table of Contents Acknowledgments .......................................................................................................................... iv Table of Contents ............................................................................................................................ v List of Tables .................................................................................................................................. x List of Figures ............................................................................................................................... xii Nomenclature ............................................................................................................................... xiv Chapter 1 - Introduction .................................................................................................................. 1 1.1 Background ......................................................................................................................... 1 1.2 Thesis Format ...................................................................................................................... 3 1.3 Objectives ........................................................................................................................... 3 Chapter 2 - Literature Review ......................................................................................................... 5 2.1 Micropollutants in the Environment .................................................................................. 5 2.1.1 Classification ........................................................................................................... 5 2.1.2 Occurrence .............................................................................................................. 6 2.1.3 Potential Impacts ..................................................................................................... 7 2.1.4 Current Status of Regulations ................................................................................. 8 2.1.5 Treatment and Removal of Micropollutants ........................................................... 9 2.2 Advanced Oxidation Processes ...................................................................................... 10 2.2.1 Mechanism and Reaction Kinetics ........................................................................ 10 2.2.2 Limitations to AOPs ............................................................................................. 13 2.2.3 Ecotoxicological Effects of UV-AOP ................................................................... 13 2.3 Pretreatment Methods for EfOM ...................................................................................... 15 2.4 Energy Requirements of AOP Processes ......................................................................... 17 2.5 References ........................................................................................................................ 19 Chapter 3 - Materials and Methods ............................................................................................... 29 3.1 Materials ........................................................................................................................... 29 3.1.2 Selection of Wastewaters ...................................................................................... 29 vi 3.1.3 Selection of Micropollutant Compounds .............................................................. 29 3.1.4 Selection of Ecotoxicological Assessment Methods ............................................ 31 3.1.5 Selection of Coagulants ........................................................................................ 32 3.2 Experimental Protocols ..................................................................................................... 33 3.2.1 Coagulation Experiments ...................................................................................... 33 3.2.3 Advanced Oxidation (UV/H2O2) Experiments ..................................................... 33 3.2.4 Background Scavenging Capacity Experiments ................................................... 35 3.2.5 Quality Control for Advanced Oxidation ............................................................. 37 3.2.6 Sampling Bottles ................................................................................................... 41 3.3 Analytical Methods ........................................................................................................... 42 3.3.1 Analysis of Micropollutant Compounds ............................................................... 42 3.3.2 Anion