TREATMENT OF SOFTDRINK INDUSTRY WASTEWATER USING AN INTEGRATED ANAEROBIC/AEROBIC MEMBRANE BIOREACTOR by INNOCENTIA GUGULETHU ERDOGAN Thesis submitted in fulfilment of the requirements for the degree Master of Technologae: Chemical Engineering in the Faculty of Engineering at the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY Supervisor: Ass. Prof. Marshall Sheldon CAPE TOWN October 2014 CPUT copyright information The thesis may not be published either in part (in scholarly, scientific or technical journals), or as a whole (as a monograph), unless permission has been obtained from the University DECLARATION I, Innocentia Gugulethu Erdogan, declare that the contents of this thesis represent my own unaided work, and that this thesis has not previously been submitted for academic examination towards any qualification. Furthermore, it represents my own opinions and not necessarily those of the Cape Peninsula University of Technology. Signed Date ii ABSTRACT Most softdrink industries in developing countries are moving towards wastewater reuse or recycling. Water and wastewater reutilization, costs of treatment and disposal guidelines, remain the most critical factors for the development of sustainable water use for softdrink industries. Wastewater reuse or recycle has potential in the softdrink industry, depending on the wastewater characteristics’ concentration and volume. During this study, an integrated laboratory scale anaerobic/aerobic sidestream membrane bioreactor (MBR) system was used for treating softdrink industry wastewater (SDIW). The aim was to evaluate the system’s performance, and identify potential opportunities to recycle the water, and therefore reduce freshwater intake and minimise wastewater production. The objectives were to: evaluate: 1) treatment efficiencies for the individual stages; 2) biogas production in the anaerobic stage; and 3) the overall performance of the integrated system under different operating conditions. The SDIW used in this study was classified as medium to high strength wastewater with a total chemical oxygen demand (CODt) ranging between 2 242 and 11 717 mg/L and a biological oxygen demand (BOD) of up to 1 150 mg/L. The major pollutants in the SDIW were caustic soda; dissolved sugars, namely fructose (1 071 mg/L) and sucrose (6 900 mg/L); with the pH ranging between 6.1 and 12. The SDIW was characterized by total suspended solids (TSS) of 66 mg/L, as well as fats, oils and greases (FOG) of 40 mg/L. The maximum turbidity and colour was 65.3 NTU and 42 mg Pt/L, respectively. All the physiochemical properties and inorganic parameters were within the within the City of Cape Town’s (CCT’s) industrial wastewater quality discharge standards by-law (South Africa, 2006). Excluding the total dissolved solids (TDS) and electrical conductivity (EC) with maximum values were 1 050 mg/L and 1 483 µS/cm, respectively. Anaerobic pre-treatment of this SDIW was studied using a laboratory-scale expanded granular sludge bed (EGSB) reactor maintained at mesophilic temperature of between 35 to 37˚C. An organic loading rate (OLR), upflow velocity (Vup) and hydraulic retention time (HRT) of 10.9 kg COD/m3d, 0.85 m/h and ~11.8 h, respectively, resulting in COD treatment - efficiencies of up to 93% CODt. An increase in nitrate (NO3 ) in the EGSB product stream + was an indication of an anaerobic ammonium (NH4 ) oxidation (ANAMMOX) process. Anaerobic digestion (AD) of SDIW in the EGSB resulted in biogas production with methane (CH4), carbon dioxide (CO2), nitrogen (N2), and oxygen (O2), concentrations of up to 70%, 3 11%, 14.8%, and 4.1%, respectively. At the OLR and Vup of 10.9 kg COD/m d and 0.85 m/h, respectively, the EGSB produced 16.7 L/d of biogas. The EGSB anaerobic pre-treatment iii resulted in stable treatment efficiencies for the removal of organic constituents, as well as biogas production without adding an external carbon source. The MBR post-treatment satisfactorily operated at a feed flowrate of up to 33.7 L/d, OLR of 2.3 and 3.1 kg COD/m3d for the anoxic and aerobic zones, respectively, and an HRT of approximately 0.41 h for both zones. The average CODt removal achieved was 86%. The dissolved oxygen (DO) concentration of 2.1 mg/L in the anoxic zone combined with an aeration rate and DO concentration of 11.8 L/min and 5.7 mg/L, in the aerobic zone resulted + - 3- in NH4 ; NO3 ; and orthophosphate (PO4 ), removal rates up to 90%; 55% and 39%, respectively. However, the MBR post-treatment did not decrease the orthophosphate concentration to within the SANS 241:2011 drinking water standards. The integrated EGSB-MBR treatment for SDIW was able to achieve an overall CODt removal 3- efficiency of up to 94%. Although the MBR performance was successful the EC, TDS, PO4 , and colour concentrations in the ultrafiltration (UF) permeate did not meet the CCT’s industrial wastewater standards by-law (2006) as well as the SANS’ drinking water standards 241:2011 and required further treatment for reuse. iv ACKNOWLEDGEMENTS I wish to thank: . The Almighty, for blessing me and giving me strength to complete this study. My sincere gratitude to my supervisor, Associate Professor Marshall Sheldon, for exceptional supervision on this project. Dr. Debbie de Jager, for her assistance and support, which I appreciate. “Ngiyabonga kakhulu dadewethu”. Our industrial partner, for agreeing to collaborate with us during this study. Without them this research would not have been possible. CPUT Transport Department for helping me to make successful the trips to obtain wastewater samples from our industrial partner. Biocatalysis and Technical Biology Research laboratory (BTB) at the Cape Peninsula University (CPUT), for allowing me to use their HPLC machine for fructose and sucrose analysis. Mr Lukhanyo Mekuto and Mr Nkosikho Dlangamandla for their moral support and confidence. Chemical Engineering: BTech students, Mr Jason August, and Luis de Sousa, for assisting me with analysis, running of the plant and collecting wastewater from the industrial partner; Ms Mantsha Maphoto and Ms Bianca Walbrugh, for assisting me with analysis and running of the plant. Biotechnology: In-service training students for assisting me to collect wastewater, perform analysis, and for the biogas samples collection. Chemical engineering staff; Mr Alwyn Bester, Mrs Hannelene Small and Mrs Elizma Alberts, for their contributions to this study. CPUT and the Engineering Faculty, for their financial assistance towards this project. I cannot begin to express my unfailing gratitude and love to my mother, Mrs Membry Mkhize, who has supported me throughout this process and has constantly encouraged me when the tasks seemed arduous and insurmountable. To my husband, Mr Naci Erdogan, who brought me back to life; I am everything I am because you loved me. Your understanding, support and encouragement during this study are appreciated. v DEDICATION To my loving and caring daughter, Céline All that I am or hope to be, I owe to you. No one will ever know the strength of my love for you. vi TABLE OF CONTENTS DECLARATION ..................................................................................................................... ii ABSTRACT ........................................................................................................................... iii ACKNOWLEDGEMENTS...................................................................................................... v DEDICATION ....................................................................................................................... vi TABLE OF CONTENTS ....................................................................................................... vii LIST OF FIGURES ............................................................................................................... xi LIST OF TABLES ................................................................................................................ xiii GLOSSARY ........................................................................................................................ xiv ABBREVIATIONS ............................................................................................................. xviii LIST OF SYMBOLS ............................................................................................................ xxi CHAPTER ONE ..................................................................................................................... 1 INTRODUCTION ................................................................................................................... 1 1.1 Background ............................................................................................................. 1 1.2 Research problem statement ................................................................................... 2 1.3 Hypotheses or research questions ........................................................................... 2 1.4 Aims and objectives ................................................................................................. 3 1.5 Significance of the research ..................................................................................... 3 1.6 Delineation of the research ...................................................................................... 3 CHAPTER TWO .................................................................................................................... 4 LITERATURE REVIEW ........................................................................................................