Activated Sludge Separation Problems : Theory, Control Measures, Practical Experiences.

Cover -- Copyright -- Dedication -- Contents -- Abbreviations -- List of Contributors -- Preface -- Chapter 1: Wastewater characterization -- 1.1 Introduction -- 1.2 Gross Parameters -- 1.3 Physical Properties -- 1.4 Organic Matter -- 1.5 Inorganic Matter -- 1.6 Micropollutants -- 1.7 Biodegradability -- 1.7.1 COD, Nitrogen and phosphorus fractionation -- 1.7.2 Evaluation methods -- References -- Chapter 2: The microbiology of the activated sludge process -- 2.1 Introduction -- 2.2 Microorganisms in Activated Sludge -- 2.2.1 Bacteria: cell structure -- 2.2.2 Inclusions -- 2.3 The Identification of Bacteria -- 2.3.1 Conventional taxonomy -- 2.3.2 Molecular taxonomy -- 2.3.3 Molecular characterization of mixed biomass -- 2.4 Filamentous Bacteria -- 2.5 Microthrix parvicella -- 2.5.1 Identification of M. parvicella -- 2.5.2 Physiology of 'Candidatus M. parvicella' -- 2.6 Thiothrix -- 2.7 Nostocoida limicola -- 2.8 Polyphosphate Accumulating Organisms (PAO) -- 2.9 Glycogen Accumulating Organisms (GAO) -- 2.10 Nitrifiers -- 2.11 Denitrifiers -- References -- Chapter 3: Activated sludge separation problems -- 3.1 Introduction -- 3.2 'Well-settling' Activated Sludge -- 3.2.1 Requirements -- 3.2.2 Microscopic features of well settling activated sludge -- 3.3 Activated Sludge Separation Problems -- 3.3.1 Poor floc microstructure -- 3.3.2 Poor floc macrostructure -- 3.3.3 Other reasons -- 3.4 Summary -- Acknowledgment -- References -- Chapter 4: Aeration tank and secondary clarifier as one system -- 4.1 Introduction -- 4.2 Aeration Tank and Secondary Clarifier Interactions -- 4.2.1 Activated sludge process -- 4.2.2 Secondary clarifier -- 4.2.3 Separation function -- 4.2.4 BOD5 -- 4.2.5 COD -- 4.2.6 Nitrogen and phosphorus -- 4.3 The Impact of Aeration Basin Equipment and Operation on the Performance of Secondary Clarifiers.

4.3.1 Mechanical vs. diffused-air aeration -- 4.3.2 Mixed liquor mixing -- 4.3.3 Degasification and reflocculation in aeration tanks -- 4.4 Features of Secondary Clarifier Construction -- 4.4.1 Inlet structure with a flocculation zone -- 4.4.2 Outlet structure -- 4.4.3 Scum baffles -- 4.5 Efficient Scum Removal from the Surface of Secondary Clarifiers -- 4.5.1 Conventional scum boxes -- 4.5.2 'Travelling' scum boxes -- 4.5.3 Pneumatic systems -- 4.6 Removal of Settled and Thickened Sludge -- 4.6.1 Effect on the final effluent quality -- 4.6.2 Mechanical scrapers -- 4.6.3 Vacuum sludge removal -- 4.7 Operation of Aeration Tank - Secondary Clarifier System for Bulking and Foaming Control -- 4.7.1 Use of chemicals in activated sludge process -- 4.7.2 Operation of secondary clarifiers -- References -- Chapter 5: Bulking and foaming control methods -- 5.1 Introduction -- 5.1.1 Microscopic characterization of the activated sludge -- 5.1.2 Biological foam -- 5.1.3 Bulking -- 5.1.4 The problem of excess sludge production and its disposal -- 5.2 Specific Control Methods -- 5.2.1 Bulking due to low (F/M) ratio -- 5.2.2 Bulking due to low dissolved oxygen concentrations -- 5.2.3 Bulking due to low nutrient concentration -- 5.2.4 Bulking due to fatty acids in the influent stream: control methods for Microthrix parvicella -- 5.2.5 Microbial and enzymatic preparations -- 5.3 Non-specific Control Methods -- 5.3.1 Oxidizing agents -- 5.3.2 Weighting or flocculating agents -- 5.3.3 Specific biocide -- 5.4 Control of Non-Filamentous Bulking ('Viscous Bulking') -- 5.5 Avoiding Poor Settling Properties: Alternative Separations of Activated Sludge -- References -- Chapter 6: Experiences in various countries -- 6.1 Introduction -- 6.2 Australia -- 6.2.1 General situation -- 6.2.2 What do we know of these filamentous bacteria?.

6.2.3 Bulking and foaming filamentous bacteria in Australian activated-sludge plants -- 6.2.4 Do filamentous bacteria populations in the same treatment plant change over time and can we control them? -- 6.2.5 The future -- 6.3 Austria -- 6.3.1 Intention of the investigation -- 6.3.2 Organization of the assessment -- 6.3.3 Methodology -- 6.3.4 Results -- 6.3.5 Summary and conclusion -- 6.4 Belgium -- 6.4.1 General situation -- 6.4.2 The M. parvicella problem -- 6.4.3 Polyaluminium chloride to tackle M. parvicella -- 6.4.4 Microthrix parvicella monitoring: a revised methodology -- 6.4.5 Conclusion -- 6.5 China -- 6.5.1 Introduction -- 6.5.2 Distribution of filamentous bacteria in activated sludge -- 6.5.3 Studies on sludge bulking processes and control strategy -- 6.6 Czech Republic -- 6.6.1 Separation problems - situation up to the 1980s -- 6.6.2 Separation problems - situation up to the mid-1990s -- 6.6.3 WWTPs screening - 1995-2000 -- 6.6.4 Results of separation problems and filamentous microorganisms screening -- 6.6.5 Development of filamentous population in Czech activated sludge plants between 1997 and 1998 -- 6.6.6 Screening of eight nutrient removal plants in 2000 -- 6.6.7 Foam control strategies -- 6.6.8 Development in the last decade -- 6.7 Denmark -- 6.7.1 General situation -- 6.7.2 MiDAS: large-scale survey of the microbiology of Danish WWTPs -- 6.7.3 Wastewater and WWTP characteristics -- 6.7.4 Settling properties in Danish nutrient removal plants -- 6.7.5 Filamentous community composition -- 6.7.6 The future: surveillance and control by DNA analyses -- 6.8 France -- 6.8.1 General situation -- 6.8.2 Current settling and foaming problems and control measures (2012 survey) -- 6.8.3 A case study: metallic salt addition in an industrial size pilot-plant subject to M. parvicella bulking and foaming -- 6.8.4 Conclusions -- 6.8.5 Acknowledgments.

6.9 Greece -- 6.9.1 General situation -- 6.9.2 Reason for dysfunctions and filamentous bacteria identified -- 6.9.3 Solution adopted -- 6.9.4 A Greek case study -- 6.10 Italy -- 6.10.1 General situation -- 6.10.2 Characterizing the activated sludge and the qualification circuit -- 6.10.3 Filament surveys -- 6.10.4 Control methods -- 6.11 Malaysia -- 6.11.1 General situation -- 6.11.2 Causes of plant dysfunction -- 6.11.3 Implemented control strategies of filamentous sludge bulking in Malaysia -- 6.11.4 Future scenario of sludge bulking occurrences in Malaysia -- 6.12 South Africa -- 6.12.1 General situation -- 6.12.2 Overview of filamentous bulking and foaming in South African wastewater treatment works -- 6.12.3 Case study -- 6.12.4 Remedial methods to control filamentous bulking and foaming in South Africa -- 6.13 Spain -- 6.13.1 General situation -- 6.13.2 Separation problems and control methods applied -- 6.13.3 Spain case study -- 6.13.4 Acknowledgement -- 6.14 USA -- 6.14.1 General situations -- 6.14.2 Control of filaments in activated sludge systems -- 6.14.3 Other solid separation problems -- 6.14.4 Foaming -- 6.14.5 Viscous bulking and dispersed growth -- 6.14.6 Conclusions -- References -- Index.

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