Evaluation of biodegradability of polystyrene materials in the managed landfill and soil

Evaluation of biodegradability of polystyrene materials in the managed landfill and soil THANH BA HO B.Sc in Biological Science, University of Natural Sciences, Vietnam M.Sc in Applied Science, RMIT University, Victoria, Australia Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) School of Environmental and Life Sciences Faculty of Science University of Newcastle (UON) New South Wales, Australia October 2018 TABLE OF CONTENTS Chapter INTRODUCTION 1.1 Background 1.2 Aim and objectives 1.3 Structure of thesis Chapter REVIEW OF LITERATURE 2.1 Polystyrene 2.2 History of polystyrene 12 2.3 Synthesis of polystyrene 12 2.4 Other polystyrene blends and copolymers 13 2.5 Uses of polystyrene 14 2.6 Treatment of polystyrene wastes and its effects on the environment and human health 15 2.7 Biodegradation of polystyrene and polystyrene blends 17 2.8 Analytical techniques used in biodegradation studies 35 2.8.1 Visual observation 35 2.8.2 Changes in mechanical properties and molar mass 35 2.8.3 Weight loss measurements: 36 2.8.4 Determination of biogas (CO2/CH4) evolution 36 2.8.5 Oxygen consumption 37 2.8.6 Clear-zone formation 37 2.8.7 Radiolabelling 37 2.9 Standard tests for plastic biodegradation 41 2.10 Issues with current standards/specifications 43 Chapter GENERAL MATERIALS AND METHODS 46 3.1 Materials 46 3.1.1 Test samples 46 3.1.2 General equipment 47 3.1.3 Chemicals 49 3.2 Methods 49 3.2.1 Overview of experiment 49 3.2.2 Design of experiments 50 3.2.3 Biodegradation studies 50 i 3.2.3.1 Visual observations 50 3.2.3.2 Determination of weight loss 50 3.2.3.3 Measurement of gas evolution 51 3.2.3.4 Field emission Scanning Electron Microscopy 51 3.2.3.5 Fourier Transform Infrared Spectroscopy 54 3.2.3.6 Gel Permeation Chromatography 55 3.2.3.7 Nuclear Magnetic Resonance spectroscopy 57 3.2.3.8 Gas Chromatography-Mass Spectrometry 58 3.2.4 Next generation sequencing analysis 60 Chapter EVALUATION OF BIODEGRADABILITY OF POLYSTYRENE MATERIALS IN A MANAGED LANDFILL 62 4.1 Introduction 62 4.2 Experimental procedure and materials 64 4.2.1 Test samples 64 4.2.2 Experimental procedure 64 4.3 Results and discussion 67 4.3.1 Monitoring of temperature and water level 68 4.3.2 Visual observation 69 4.3.3 Surface imaging of test samples 73 4.3.4 Fourier Transform Infrared Spectroscopy 78 4.3.5 Gel Permeation Chromatography 82 4.3.6 Nuclear Magnetic Resonance spectroscopy 83 4.3.7 Determination of weight loss 85 4.4 Conclusions 87 Chapter EVALUATION OF BIODEGRADABILITY OF POLYSTYRENE MATERIALS IN LABORATORY CONDITIONS 88 5.1 Introduction 88 5.2 Materials and methods 89 5.2.1 Test design 89 5.2.2 Calculation of the percent of biodegradation 91 5.3 Results and discussion 91 5.3.1 Gas measurement 91 5.3.2 Visual observation 92 5.3.3 Field emission Scanning Electron Microscopy 94 5.3.4 Fourier Transform Infrared Spectroscopy 96 5.3.5 Nuclear Magnetic Resonance spectroscopy 101 5.3.6 Determination of weight loss 104 ii 5.4 Conclusions 104 Chapter INVESTIGATION OF BIODEGRADABILITY OF POLYSTYRENE MATERIALS IN GARDEN SOIL 106 6.1 Introduction 106 6.2 Materials and methods 107 6.3 Results and discussion 108 6.3.1 Visual observation 108 6.3.2 Field emission Scanning Electron Microscopy 110 6.3.3 Fourier Transform Infrared Spectroscopy 113 6.3.4 Nuclear Magnetic Resonance spectroscopy 117 6.4 Conclusions 120 Chapter BACTERIAL ISOLATION AND INVESTIGATION OF BIODEGRADABILITY OF MODIFIED POLYSTYRENE BY ISOLATED BACTERIA 121 7.1 Introduction 121 7.2 Materials and methods 122 7.2.1 Materials 122 7.2.2 Methods 123 7.3 Results and discussion 125 7.3.1 Determination of weight loss 125 7.3.2 Field emission Scanning Electron Microscopy 127 7.3.3 Fourier Transform Infrared Spectroscopy 129 7.3.4 Gel Permeation Chromatography 131 7.3.5 Nuclear Magnetic Resonance spectroscopy 131 7.3.6 Gas Chromatography-Mass Spectrometry 133 7.4 Conclusions 135 Chapter BACTERIAL IDENTIFICATION IN THE LANDFILL 136 8.1 Introduction 136 8.2 Materials and methods 137 8.3 Results and discussion 139 8.4 Conclusions 147 Chapter SUMMARY AND CONCLUSIONS 148 9.1 Research concept 148 9.2 Research components and processes involved 150 9.2.1 Biodegradability of polystyrene in a managed landfill 150 iii 9.2.2 Biodegradability of polystyrene in landfill leachate under laboratory conditions 151 9.2.3 Biodegradability of polystyrene in garden soil 152 9.2.4 Bacterial isolation and polystyrene biodegradation by isolated bacteria 153 9.2.5 Identification of microbial communities in a managed landfill and in leachate 153 9.3 General conclusion and application of this research 154 9.4 Future research 156 REFERENCES 159 iv LIST OF FIGURES CHAPTER Figure 1.1 Types of popular plastics used in the market Figure 1.2 The percentage of plastics used in Australia Figure 1.3 Estimated time range for plastic degradation in the marine environment Figure 1.4 Summarized diagram of the research CHAPTER Figure 2.1 Polymerization of styrene to produce polystyrene Figure 2.2 Structural types of polystyrene 10 Figure 2.3 Production of EPS and HIPS pellets 13 CHAPTER Figure 3.1 Polystyrene samples used in this project 47 Figure 3.2 FESEM analytical processes 53 Figure 3.3 FTIR spectrometer systems used to analyse the polystyrene test samples 55 Figure 3.4 Gel Permeation Chromatography system used to analyse the polystyrene test samples 56 Figure 3.5 Nuclear Magnetic Resonance spectroscopy system used to analyse the polystyrene samples 58 Figure 3.6 GC-MS system used to analyse the polystyrene test samples 59 CHAPTER Figure 4.1 Map of location of test site marked with a red point 64 Figure 4.2 Diagram of location of samples in the landfill test seen from above 65 Figure 4.3 Housing cases used for the test in the landfill 66 Figure 4.4 Longitudinal section of a sample in the landfill test (left) and diagram of all test samples after being installed into the landfill (right) 66 Figure 4.5 Temperature (oC) data from inside the Summerhill landfill at 11m depth from Nov 2015 to Oct 2016 69 Figure 4.6 Level of leachate data from inside the Summerhill landfill at 11 m depth from Nov 2015 to Oct 2016 69 Figure 4.7 HIPS lids after incubation inside the landfill in for 356 days (left) and 76 days (right) 71 v Figure 4.8 MPS cups after incubation inside the landfill: Photo a) & c): inside and outside of the cup after 356 days; photo b) & d): inside and outside of the cup after 76 days 72 Figure 4.9 MPS cups stained with iodine solution: test sample after 76 days inside the Summerhill landfill (left), and control sample (right) 73 Figure 4.10 FESEM micrographs of modified polystyrene foam cups (10,000X) Control sample (top), and the test sample after being buried in the landfill for 356 days (bottom) 75 Figure 4.11 FESEM micrographs of modified polystyrene foam cups (100X): test sample after being buried in the landfill for 356 days (bottom) compared to control sample (top) 76 Figure 4.12 FESEM micrographs of HIPS lids (10,000X): control sample (top) and the test sample after being buried in the landfill for 356 days (bottom) 77 Figure 4.13 FTIR spectra of MPS of control sample (top), and samples after 356 days in the landfill (bottom) 79 Figure 4.14 FTIR spectra of PS of control sample (top), and samples after 356 days in the landfill (bottom) 80 Figure 4.15 FTIR spectra of HIPS of control sample (top), and samples after 356 days in the landfill (bottom) 81 Figure 4.16 1H NMR analysis of polystyrene foamed cups (MPS) 84 Figure 4.17 Weight changes of the test samples in the landfill after different test times 86 Figure 4.18 Surface of MPS foam cup inside the landfill for 356 days after washing 86 CHAPTER Figure 5.1 Diagram of laboratory test (top) and a photo of lab test (bottom) 90 Figure 5.2 MPS samples treated with iodine solution after 90 days in the leachate (right) compared with control sample (left) 94 Figure 5.3 FESEM micrographs at 10,000x magnification of polystyrene foam cups (PS) in the lab test after 90 days: negative control sample (left), treated sample (right) 95 Figure 5.4 FESEM micrographs at 10,000x magnification of modified polystyrene foam cups (MPS) in the lab test after 90 days: negative control samples (left), treated sample (right) 95 Figure 5.5 FESEM micrographs at 10,000x magnification of HIPS lid in the lab test after 90 days: control sample (left), treated sample (right) 96 vi Figure 5.6 FTIR spectra of HIPS New peaks seen in the treated sample have been circled in red and green 98 Figure 5.7 FTIR spectra of MPS New peaks seen in the treated sample have been circled in red 99 Figure 5.8 FTIR spectra of PS The top graph is control sample and the bottom graph is the treated sample 100 Figure 5.9 1H NMR spectrum of modified polystyrene foam cups (MPS): control sample (top) and the treated sample (bottom) 102 Figure 5.10 1H NMR spectrum of Dart® foam cups (PS): control sample (top) and the treated sample (bottom) 103 CHAPTER Figure 6.1 Images of garden soil biodegradation experiment 108 Figure 6.2 Images of inside and outside surfaces of a foam cup after six months in soil (right) compared to the control (left) 109 Figure 6.3 FESEM micrographs of modified polystyrene foam cups (MPS) of blank sample (top) and test sample in the soil (bottom) at 10,000x magnification 111 Figure 6.4 FESEM micrographs of polystyrene foam cups (PS) of blank sample (top) and test sample in soil for six months (bottom) at 10,000x magnification 112 Figure 6.5 FTIR spectra of blank sample of MPS (A) and treated sample of MPS in soil for six months (B) 115 Figure 6.6 FTIR spectra of blank sample of PS (A) and treated sample of PS in soil for six months (B) 116 Figure 6.7 1H NMR spectra of PS of a blank sample (a), and a test sample in soil for months (b) 118 Figure 6.8 1H NMR spectra of MPS of a blank sample (a), and a test sample in soil for months (b) 119 CHAPTER Figure 7.1 Thin Film Modified polystyrene discs (TFMP) made by surface casting 123 Figure 7.2 Diagram of bacteria isolation from leachate with polystyrene film thickness 0.025 mm as substrate 124 Figure 7.3 Change in weight of the TFMPS test samples after 90 days incubation with isolated bacterial strains (error bars represent standard deviation) 126 Figure 7.4 FESEM micrographs of a control sample of TFMPS at magnification of 5,000x (top) and 10,000x (bottom) 128 vii Figure 7.5 FESEM micrographs of treated samples at 10,000x magnification TFMPS was treated with strains of (a) F1; (b) F2; (c) F5; (d) F7 129 Figure 7.6 FTIR spectra of TFMPS film treated with isolated strain F8 130 Figure 7.7 1H NMR spectrum of a control sample of TFMPS film 132 Figure 7.8 1H NMR spectrum of TFMPS treated with F2 strain 132 Figure 7.9 1H NMR spectrum of TFMPS treated with F8 strain 133 Figure 7.10 GC-MS graph of biodegradation products of TFMPS polystyrene by strain F8 134 CHAPTER Figure 8.1 Relative abundance of microorganisms at phylum level (level 2) of taxonomy in solid and leachate phase of landfill 141 Figure 8.2 Relative abundance of microorganisms at class level (level 3) of taxonomy in solid and leachate phase of landfill 142 Figure 8.3 Relative abundance of microbial communities in leachate at phylum level (level 2) 143 Figure 8.4 Relative abundance of microbial communities in leachate at Class level (level 3) 144 viii LIST OF TABLES Chapter Table 2.1 Summary of industrial applications of polystyrene (American Chemistry Council 2015) 11 Table 2.2 Plastic waste generation and recovery in the United States, 2012 15 Table 2.3 Typical commercial additives used with polystyrene 19 Table 2.4 Summary of studies on biodegradability of polystyrene and modified polystyrene 21 Table 2.5 Existing techniques for assessment of polystyrene biodegradation 39 Table 2.6 Standard tests for biodegradation of plastic materials 41 Chapter Table 3.1 List of general equipment used in the project 48 Chapter Table 4.1 Types and quantity of testing samples in the Summerhill landfill 67 Table 4.2 Estimation of colour change of the test samples 70 Table 4.3 Estimation of surface change of the test samples 74 Table 4.4 Summary of changes in FTIR spectroscopy of the test samples 79 Table 4.5 GPC analysis of foam cups (MPS and PS) treated in the Summerhill landfill for different periods of time 83 Chapter Table 5.1 Quantities of test samples in the laboratory conditions 91 Table 5.2 Summary of weight of test samples before and after laboratory testing 104 ix ... Housing cases used for the test in the landfill 66 Figure 4.4 Longitudinal section of a sample in the landfill test (left) and diagram of all test samples after being installed into the landfill. .. However, polystyrene is very stable and extremely hard to degrade in the environment after disposal The scarcity of landfill space, hazards of waste incineration and increasing costs of disposing of. .. after incubation inside the landfill in for 356 days (left) and 76 days (right) 71 v Figure 4.8 MPS cups after incubation inside the landfill: Photo a) & c): inside and outside of the