Innovative Biological Destruction of Hazardous Chlorinated and Brominated Volatile Disinfection By-Products Using Biotrickling Filters A Dissertation submitted to the Division of Research and Advanced Studies of the University of Cincinnati in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY in the Department of Chemical and Environmental Engineering of College of Engineering and Applied Sciences 2017 By Bineyam Hadgu Mezgebe MCP, University of Cincinnati, 2009 Post Graduate Diploma, Berlin University of Applied Sciences, Berlin, Germany 1999 Committee Dr. George A. Sorial (chair) Dr. Margaret J. Kupferle Dr. David Wendell Dr. Endalkachew Sahle-Demessie Dr. Ashraf Aly Hassan I | P a g e Abstract Disinfection by products (DBPs) resulted from the reactions between the chlorine and natural organic substances which increased the formation of trihalomethanes (THMs). DBPs are carcinogens or have been known to cause health risks. Chloroform (CF) is the most abundant of all THMs with a maximum contaminant level (MCL) of 0.070 mg/L. In addition, CF and other THMs could also originate from sources other than by-products of water disinfection. Several physical and chemical removal methods are used to treat chloroform, which are expensive and could generate secondary pollutants. Biofiltration is one of the most proven technologies for volatile organic compound (VOC) control as it is environment–friendly, cost effective and releases fewer byproducts. In this study, an integrated technology was proposed. The integrated technology consists of nitrogen or air stripping followed by anaerobic or aerobic bio-trickling Filter (BTF). This study evaluated first CF only and secondly mixtures of THMs (CF and dichlorobromomethane (DCBM)). A co metabolite (ethanol) and surfactant (Tomadol 25 – 7) have been used to improve the biodegradation process. In addition, surfactin a bio surfactant was seeded within the BTF and its effectiveness has been investigated. Finally, microbial analysis was conducted to determine the dominant and responsible microbes for the BTFs performance. In the anaerobic BTF, a co metabolite and surfactant were utilized to enhance the biodegradation process. Upon the addition of ethanol and Tomadol 25 - 7, the performance of the anaerobic reactor improved from an initial 49% to over 64% removal efficiency of CF. On the other hand, the average removal efficiency of CF for aerobic fungi BTF under acidic condition was 80%. For both cases the initial CF loading rate was constant at 0.27 g /m3.hr. The microbial community analysis suggested that A. oryzae and A. restrica were the dominant and responsible II | P a g e bacteria species observed in the anaerobic BTF. Fusarium sp. and F. solani were the dominant fungi responsible for higher CF degradation. In practice, a BTF will be exposed to mixtures of THMs and other VOCs emitted together. In this regard, two other independent BTFs were studied to remove mixtures of THMs (CF and DCBM). These two independent BTFs, one with co metabolite and another one with bio surfactant were investigated in removing the stripped THMs. Adding co metabolite at highest loading rate resulted in removal efficiencies of 85% for CF and 87% for DCBM. Whereas at the same THMs loading rate condition, the use of surfactin without co metabolite showed a removal efficiency of 85% and 80% for CF and CBM, respectively. The microbial community analysis suggested that Fusarium sp. was the most dominant fungi for the BTF with co metabolite. Whereas, Fusarium oxysporum was the dominant microbes for the BTF with surfactin. III | P a g e IV | P a g e Acknowledgments I would like to express my deepest appreciation to my advisor, Dr. George A. Sorial, for his guidance, help, and support throughout my journey at the University of Cincinnati. His continuous pursuit of perfection and demand for scientific excellence was a major driving force behind this work. He has helped me a great deal in reaching my goals as a doctoral candidate and as a future researcher. I would like to thank my mentor Dr. Endalkachew Sahle-Demessie for his help and guidance throughout my doctorial work. I also would like to thank my friend and mentor Dr. Ashraf Aly Hassan for his guidance on my research early-on with my laboratory work and later on finishing my research. Moreover, I would like to give appreciation to my committee members, Dr. Margaret J. Kupferle, and Dr. David Wendell for their support and contribution. I gratefully acknowledge the United States Environmental Protection Agency (USEPA) for the grant that I received during my research. I would like to thank all my colleagues and friends at University of Cincinnati: Ayenachew Tegenu, Hengye Jing, Abderrahman Zehraoui, Hafiz Salih, Shahram Ghasemzadeh and Palanisamy, K for making this journey enjoyable and memorable. I would like to thank all my group members and all my friends for all the needed encouragement and support Finally, I dedicate this work to my parents, especially for my Mom, who made me believe in my abilities to pursue the PhD, my wife, who has endured with me all the challenges I have faced during the program, my sister, who always provided me with moral support. V | P a g e Table of Contents Abstract ................................................................................................................................. II Acknowledgments ...................................................................................................................... V Table of Contents ......................................................................................................................VI List of Tables ............................................................................................................................. X List Figures ...............................................................................................................................XI 1. Introduction ............................................................................................................................. 1 1.1 Background ........................................................................................................................... 1 1.2 Significance of the study ....................................................................................................... 2 1.2.1 DBPs exposure, related health risks and regulations ........................................................... 2 1.2.2 Current controlling techniques and their challenges ............................................................ 4 1.3 Biofiltration and THMs ......................................................................................................... 5 1.4 Specific project objective and innovative concept of biofiltration .......................................... 6 1.5 Objectives ............................................................................................................................. 7 1.5.1 Gas stripping of trihalomethanes (THMs) from water ......................................................... 7 1.5.2 Batch studies ...................................................................................................................... 8 1.5.3 Anaerobic vs aerobic conditions for the degradation of chlorinated compounds .................. 9 1.6 Structure of dissertation ....................................................................................................... 11 1.7 References ........................................................................................................................... 16 Chapter 2 The Effectiveness of Aeration of Drinking Water to Control Trihalomethanes from Publicly Water System ............................................................................................. 18 2.1 Abstract ............................................................................................................................... 18 2.2 Introduction ......................................................................................................................... 19 2.3 Experimental methods and analysis ..................................................................................... 22 2.3.1 Materials and methods ...................................................................................................... 22 2.3.2 Bench-scale bubble aeration experiment for THMs........................................................... 23 2.3.3 Thermal stratification in the large water storage tanks ...................................................... 23 2.4 Results and Discussion ........................................................................................................ 25 2.4.1 Result from lab scale bubble aeration experiment ............................................................. 25 2.4.2 Bubble aeration modeling for THMs removal ................................................................... 26 2.4.2.1Bubble aeration mathematical modeling - I ..................................................................... 26 VI | P a g e 2.4.2.2 Mathematical modeling of bubble aeration - II ............................................................... 27 2.4.2.3 Model parameter estimations ......................................................................................... 29 2.4.4 Comparing bench scale bubble aeration study with model prediction ................................ 31 2.4.5 Bubble aeration and temperatures stratification in large tank ...........................................