by Chung Wai Ki. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1992. / Includes bibliographical references (leaves 110-120). / Acknowledgments --- p.i / Abstract --- p.ii / Table of Content --- p.iii / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Sewage Treatment --- p.1 / Chapter 1.1.1 --- Overview --- p.1 / Chapter 1.1.2 --- Types of Treatment --- p.2 / Chapter 1.2 --- Activated Sludge Process --- p.3 / Chapter 1.2.1 --- Overview --- p.3 / Chapter 1.2.2 --- Biology of Activated Sludge --- p.3 / Chapter 1.2.3 --- Operation of the Activated Sludge Process --- p.4 / Chapter 1.2.4 --- Floe Formation in Activated Sludge Process --- p.10 / Chapter 1.2.5 --- Operational Problems Associated with the Activated Sludge Process --- p.12 / Chapter 1.2.5.1 --- Bulking --- p.12 / Chapter 1.2.5.2 --- Foaming --- p.14 / Chapter 1.3 --- Foaming in Activated Sludge Process --- p.15 / Chapter 1.3.1 --- Overview --- p.15 / Chapter 1.3.2 --- Causes of Foaming --- p.16 / Chapter 1.3.2.1 --- Biology of Nocardia --- p.18 / Chapter 1.3.2.2 --- Growth Strategy of Nocardia --- p.18 / Chapter 1.3.2.3 --- Metabolic Specialization of Nocardia amarae --- p.19 / Chapter 1.3.3 --- Controls of Foaming --- p.20 / Chapter 1.4 --- Microbial Lipid and Bacterial Foaming --- p.23 / Chapter 1.4.1 --- Overview --- p.23 / Chapter 1.4.2 --- Fatty Acids in Bacteria --- p.24 / Chapter 1.4.3 --- Analytical Techniques --- p.25 / Chapter 1.4.3.1 --- Chromatography --- p.25 / Chapter 1.4.3.2 --- Gas Chromatography - Mass Spectrometry (GC-MS) --- p.26 / Chapter 1.4.4 --- Significance of Fatty Acids to Foaming --- p.27 / Chapter 1.5 --- Disinfection --- p.29 / Chapter 1.5.1 --- Overview --- p.29 / Chapter 1.5.2 --- Types of Disinfectants --- p.30 / Chapter 1.5.3 --- Mechanism of Disinfection --- p.31 / Chapter 1.5.4 --- Disinfection with Chlorine and Hypochlorite --- p.31 / Chapter 1.5.5 --- Chemistry of Chlorine Disinfection --- p.32 / Chapter 2. --- Objectives of Study --- p.35 / Chapter 3. --- Materials and Methods --- p.37 / Chapter 3.1 --- Sample Collection: --- p.37 / Chapter 3.2 --- Biological Studies of Activated Sludge Samples --- p.37 / Chapter 3.2.1 --- Microscopic Examination --- p.37 / Chapter 3.2.2 --- Isolation of Foam-Causing Filamentous Bacteria --- p.38 / Chapter 3.3 --- Physiology Studies of Nocardia amarae --- p.39 / Chapter 3.3.1 --- Growth Kinetics --- p.40 / Chapter 3.3.2 --- Effects of Fatty Acids on Nocardia amarae --- p.40 / Chapter 3.3.2.1 --- Fatty Acids as Sole Carbon Source --- p.41 / Chapter 3.3.2.2 --- Growth Stimulation --- p.42 / Chapter 3.3.2.3 --- Foam Test --- p.43 / Chapter 3.4 --- Fatty Acids Analysis --- p.43 / Chapter 3.4.1 --- Fatty Acid Extraction --- p.43 / Chapter 3.4.2 --- GC Analysis --- p.45 / Chapter 3.4.3 --- GC-MS Analysis --- p.46 / Chapter 3.5 --- Laboratory-Scale Activated Sludge Unit --- p.46 / Chapter 3.5.1 --- Set Up --- p.46 / Chapter 3.5.2 --- Performance Assessment of Laboratory-Scale Unit --- p.52 / Chapter 3.5.2.1 --- Physical Parameters --- p.52 / Chapter 3.5.2.2 --- Chemical Parameters --- p.54 / Chapter 3.5.2.3 --- Biological Parameters --- p.55 / Chapter 3.5.3 --- Anoxic Condition --- p.56 / Chapter 3.6 --- Toxicity Studies --- p.56 / Chapter 3.6.1 --- Comparative Toxicity Studies in Pure Culture --- p.56 / Chapter 3.6.2 --- Chlorination Studies of the Laboratory-Scale Unit --- p.58 / Chapter 3.6.3 --- Residual Chlorine Measurement --- p.58 / Chapter 3.7 --- Scanning Electron Microscopy --- p.60 / Chapter 4. --- Results --- p.61 / Chapter 4.1 --- Biological Studies of Activated Sludge --- p.61 / Chapter 4.1.1 --- Microscopic Examination --- p.61 / Chapter 4.1.2 --- Isolation of Foam-Causing Filamentous Bacteria --- p.61 / Chapter 4.2 --- Physiological Studies of Nocardia amarae --- p.65 / Chapter 4.2.1 --- Growth Kinetics --- p.65 / Chapter 4.2.2 --- Effects of Fatty Acids on Nocardia amarae --- p.69 / Chapter 4.2.2.1 --- Fatty Acids as Sole Carbon Source --- p.69 / Chapter 4.2.2.2 --- Growth Stimulation --- p.69 / Chapter 4.2.2.3 --- Foam Test --- p.69 / Chapter 4.3 --- Fatty Acids Analysis --- p.75 / Chapter 4.4 --- Laboratory-Scale Activated Sludge Unit --- p.80 / Chapter 4.4.1 --- Assessment of Performance of the Laboratory-Scale Unit --- p.80 / Chapter 4.4.2 --- Under Anoxic Condition --- p.80 / Chapter 4.5 --- Toxicity Studies --- p.85 / Chapter 4.5.1 --- Comparative Toxicity Studies in Pure Culture --- p.85 / Chapter 4.5.2 --- Chlorination Studies of Laboratory-Scale Unit --- p.85 / Chapter 4.5.3 --- Residual Chlorine Measurement --- p.91 / Chapter 5. --- Discussion --- p.94 / Chapter 5.1 --- Biological Studies of Activated Sludge Samples --- p.94 / Chapter 5.1.1 --- Microscopic Examination --- p.94 / Chapter 5.1.2 --- Isolation of Foam-Causing Filamentous Bacteria --- p.95 / Chapter 5.2 --- Physiological Studies of Nocardia amarae --- p.96 / Chapter 5.2.1 --- Growth Kinetics --- p.96 / Chapter 5.2.2 --- Effects of Fatty Acids on Nocardia amarae --- p.96 / Chapter 5.2.2.1 --- Fatty Acids as Sole Carbon Source --- p.96 / Chapter 5.2.2.2 --- Growth Stimulation --- p.97 / Chapter 5.2.2.3 --- Foam Test --- p.98 / Chapter 5.3 --- Fatty Acids Analysis --- p.99 / Chapter 5.4 --- Laboratory-Scale Activated Sludge Unit --- p.101 / Chapter 5.4.1 --- Assessment of Performance of the Laboratory-Scale Unit --- p.102 / Chapter 5.4.2 --- Under Anoxic Condition --- p.103 / Chapter 5.5 --- Toxicity Studies --- p.103 / Chapter 5.5.1 --- Comparative Toxicity Studies in Pure Culture --- p.103 / Chapter 5.5.2 --- Chlorination Studies of the Laboratory-Scale Unit --- p.105 / Chapter 6. --- Conclusion --- p.107 / Chapter 7. --- Summary --- p.108 / Chapter 8. --- References --- p.110

by Sonia, Tze Yan Lo. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 132-147). / Abstracts in English and Chinese. / Acknowledgments --- p.i / Abstract --- p.ii / Table of Content --- p.iii / List of Figures --- p.ix / List of Tables --- p.xiii / List of Abbreviations --- p.xv / Terminology --- p.xvii / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Objectives of sewage treatment process --- p.1 / Chapter 1.1.1 --- Types of treatment --- p.1 / Chapter 1.1.2 --- Activated sludge process --- p.2 / Chapter 1.1.3 --- Functioning of activated sludge process --- p.2 / Chapter 1.2 --- Common microbially mediated solid separation problems --- p.4 / Chapter 1.3 --- Bacterial foaming --- p.4 / Chapter 1.4 --- Factors enhancing foam production --- p.5 / Chapter 1.4.1 --- Substrates present in sewage --- p.6 / Chapter 1.4.2 --- Operating conditions --- p.8 / Chapter 1.4.3 --- Overpopulation of foaming bacteria --- p.8 / Chapter 1.5 --- Bacteria reported for foaming --- p.9 / Chapter 1.5.1 --- Foaming bacteria reported in different countries --- p.9 / Chapter 1.5.2 --- Nocardia Biology --- p.10 / Chapter 1.6 --- Metaboilsm of hydrophobic substances in sewage --- p.11 / Chapter 1.6.1 --- Metabolism of alkanes --- p.11 / Chapter 1.6.2 --- Metabolism of grease and oils --- p.11 / Chapter 1.6.3 --- Functions of lipids in the formation of bacterial foam --- p.11 / Chapter 1.7 --- Competition between floc-formers and foam-formers --- p.12 / Chapter 1.7.1 --- Interactions between microbial populations in activated sludge process --- p.12 / Chapter 1.7.2 --- Monod relationship and kinetic selection --- p.15 / Chapter 1.7.3 --- Effects of grease and oils in dominance of foaming bacteria --- p.17 / Chapter 1.8 --- Suggested mechanisms for bacterial foaming --- p.18 / Chapter 1.8.1 --- Mechanism suggested in early stage --- p.18 / Chapter 1.8.2 --- Froth flotation theory --- p.18 / Chapter 1.9 --- Problems from foaming --- p.21 / Chapter 1.10 --- Control of filamentous bacterial foaming --- p.22 / Chapter 2. --- Objectives of the study --- p.26 / Chapter 3. --- Materials and Methods --- p.27 / Chapter 3.1 --- Sample collection --- p.27 / Chapter 3.2 --- Isolation of major foaming and non-foaming bacteria --- p.27 / Chapter 3.2.1 --- Isolation of foaming bacteria --- p.27 / Chapter 3.2.2 --- Isolation of non-foaming bacteria --- p.30 / Chapter 3.3 --- "Physiological studies on type strain Nocardia amarae ATCC 27810, isolated major foaming bacterium, Nocardia sp. CU-2 and non- foaming bacterium, Aeromonas sp. CU-1" --- p.31 / Chapter 3.4 --- Effects of fatty acids on growth kinetics of Nocardia sp. CU-2 and Aeromonas sp. CU-1 in pure culture --- p.32 / Chapter 3.5 --- Effects of fatty acids on growth yields of Nocardia sp. CU-2 and Aeromonas sp. CU-1 in pure culture --- p.34 / Chapter 3.6 --- Effects of fatty acids on growth yields of Nocardia sp. CU-2 and Aeromonas sp. CU-1 in mixed culture --- p.37 / Chapter 3.7 --- Effect of fatty acids on the propensity of foam formation of Nocardia sp. CU-2 growing with different fatty acids --- p.38 / Chapter 3.8 --- Effects of fatty acids on hydrocarbon affinity (HA) of Nocardia sp CU-2 --- p.39 / Chapter 3.9 --- "Effects of fatty acids on the filamentous growth, nocardial growth, foaming abilities and settling abilities of activated sludge in batch cultures of foaming and non-foaming samples" --- p.43 / Chapter 4. --- Results --- p.48 / Chapter 4.1 --- Isolation of foaming and non-foaming bacteria --- p.48 / Chapter 4.1.1 --- Isolation of foaming bacteria --- p.48 / Chapter 4.1.2 --- Isolation of non-foaming bacteria --- p.48 / Chapter 4.2 --- "Physiological studies on type strain Nocardia amarae ATCC 27810, isolated major foaming bacterium, Nocardia sp. CU-2 and non- foaming bacterium, Aeromonas sp. CU-1" --- p.56 / Chapter 4.3 --- Effects of fatty acids on growth kinetics of Nocardia sp. CU-2 and Aeromonas sp. CU-1 in pure culture --- p.56 / Chapter 4.4 --- Effects of fatty acids on growth yields of Nocardia sp. CU-2 and Aeromonas sp. CU-1 in pure culture --- p.60 / Chapter 4.4.1 --- Effects of fatty acids on Nocardia sp. CU-2 --- p.77 / Chapter 4.4.2 --- Effects of fatty acids on Aeromonas sp. CU-1 --- p.77 / Chapter 4.5 --- Effects of fatty acids on growth yields of Nocardia sp. CU-2 and Aeromonas sp. CU-1 in mixed culture --- p.78 / Chapter 4.6 --- Effect of fatty acids on the propensity of foam formation of Nocardia sp. CU-2 growing with different fatty acids --- p.78 / Chapter 4.7 --- Effects of fatty acids on hydrocarbon affinity (HA) of Nocardia sp CU-2 --- p.83 / Chapter 4.8 --- "Effects of fatty acids on the filamentous growth, nocardial growth, foaming abilities and settling abilities of activated sludge in batch cultures of foaming and non-foaming samples" --- p.103 / Chapter 4.8.1 --- The filamentous growth of activated sludge --- p.103 / Chapter 4.8.2 --- Nocardial count --- p.103 / Chapter 4.8.3 --- Foam ratings --- p.107 / Chapter 4.8.4 --- Sludge settling ability --- p.107 / Chapter 5. --- Discussion --- p.114 / Chapter 5.1 --- "Physiological studies on type strain Nocardia amarae ATCC 27810, isolated major foaming bacterium, Nocardia sp. CU-2 and non- foaming bacterium, Aeromonas sp. CU-1" --- p.114 / Chapter 5.2 --- Effects of fatty acids on growth kinetics of Nocardia sp. CU-2 and Aeromonas sp. CU-1 in pure culture --- p.114 / Chapter 5.2.1 --- Inhibition effects of MC fatty acids on growth of Nocardia sp. CU-2 --- p.115 / Chapter 5.2.2 --- Effects of fatty acids on specific growth rates --- p.115 / Chapter 5.2.3 --- Length of lag phase --- p.115 / Chapter 5.2.4 --- Kinetic selection of Nocardia sp. CU-2 and Aeromonas sp. CU-1 --- p.116 / Chapter 5.3 --- Effects of fatty acids on growth yields of Nocardia sp. CU-2 and Aeromonas sp. CU-1 in pure culture --- p.117 / Chapter 5.3.1 --- Growth of Nocardia sp. CU-2 and Aeromonas sp. CU-1 in different media --- p.117 / Chapter 5.3.2 --- "Effects of fatty acids on Nocardia sp, CU-2" --- p.118 / Chapter 5.3.3 --- Effects of fatty acids on Aeromonas sp. CU-1 --- p.119 / Chapter 5.4 --- Effects of fatty acids on growth yields of Nocardia sp. CU-2 and Aeromonas sp. CU-1 in mixed culture --- p.119 / Chapter 5.4.1 --- Effects of fatty acids in NB --- p.119 / Chapter 5.4.2 --- Effects of fatty acids in MM --- p.120 / Chapter 5.4.3 --- Effects of fatty acids in SS --- p.121 / Chapter 5.5 --- Effect of fatty acids on the propensity of foam formation of Nocardia sp. CU-2 growing with different fatty acids --- p.122 / Chapter 5.6 --- Effects of fatty acids on hydrocarbon affinity (HA) of Nocardia sp CU-2 --- p.122 / Chapter 5.6.1 --- Differences in HA of Nocardia sp. CU-2 among three hydrocarbons --- p.122 / Chapter 5.6.2 --- Differences in HA of Nocardia sp. CU-2 among three different media --- p.123 / Chapter 5.6.3 --- Effects of fatty acids on HA of Nocardia sp. CU-2 --- p.123 / Chapter 5.7 --- "Effects of fatty acids on the filamentous growth, nocardial growth, foaming and settling abilities of activated sludge in batch cultures" --- p.124 / Chapter 5.7.1 --- Abundance of filamentous microorganisms in activated sludge --- p.124 / Chapter 5.7.2 --- Nocardial count --- p.124 / Chapter 5.7.3 --- Foam ratings --- p.125 / Chapter 5.7.4 --- Sludge settling ability --- p.126 / Chapter 6. --- Conclusion --- p.127 / Chapter 7. --- Summary --- p.129 / Chapter 8. --- References --- p.132