Structure, Function and Formation of Anaerobic Granular Sludge

Transcription

1 Structure, Function and Formation of Anaerobic Granular Sludge Von der Fakultat Architektur, Bauingenieurwesen und Umweltwissenschaften der Technischen Universitat Carolo-Wilhelmina zu Braunschweig zur Erlangung des Grades eines Doktoringenieurs (Dr.-Ing.) genehmigte Dissertation von Samir Naser Hag Ibrahim geboren am aus Beirut - Libnan Eingereicht am Disputation am 30. September November 2008 Berichterstatter Berichterstatterin Berichterstatter Prof. Dr.-Ing. Norbert Dichtl Prof. Dr. rer. nat. habil. Kornelia Smalla PD Dr.- Ing. Thomas Dockhorn 2008

2 Table of Contents 1 General Introduction and Research Objectives General Introduction Research Objectives 3 2 Background and Literature Review Introduction The Anaerobic Degradation Process Hydrolysis Acidogenesis/Fermentation Acetogenesis Methanogenesis Microbiology of Anaerobic Digestion Fermentative Bacteria Hydrogen Producing Acetogenic Bacteria Homoacetogenic Bacteria Methanogenic Bacteria Sulfate-Reducing Bacteria Types of Anaerobic Granular Sludge Reactors Upflow Anaerobic Sludge Bed (UASB) Reactor Expanded Granular Sludge Bed (EGSB) Reactor Anaerobic Migrating Blanket Reactor (AMBR) Anaerobic Sequencing Batch Reactor (ASBR) Internal Circulation (IC) Reactor Anaerobic hybrid (AH) reactor Characteristics of Anaerobic Granules Microstructure Methanogenic Activity Surface Properties Apparent Color Density and Size Mechanical Strength 24

3 2.5.7 Extracellular Polymeric Substances (EPS) Major Factors Influencing Anaerobic Granulation Upflow Velocity and Hydraulic Retention Time Organic Loading Rate (OLR) Characteristics of Substrate Characteristics of Seed Sludge Addition of Polymer Addition of Cations Reactor Temperature Reactor ph Mechanisms and Models for Anaerobic Granulation Thermodynamic Models Secondary Minimum Adhesion Model Hydrophobic Interaction and Local Dehydration Models Surface Tension Model Structural Models Inert Nuclei Model Divalent Cation-Bridge Model EPS Binding Model The Cape Town Model 'Spaghetti'Theory Crystallized Nuclei Formation Model Syntrophic Microcolony Model Proton Translocation-Dehydration Theory Dehydration of Bacterial Surfaces References 42 3 Bulk Properties of Anaerobic Granular Sludge from Different Full-Scale Anaerobic Reactors Introduction Materials and Methods Source of Granular Sludges Bulk Physical Properties 55 II

4 VS.TS and SVI Density Settling Velocity Granule Shape Characteristics Granule Strength Sludge Surface Properties Hydrophobicity Test Zeta Potential Extracellular Polymeric Substances (EPS) Statistical Data Analysis Results Granular Sludge Physical and Morphological Properties Settling Velocity, SVI, Strength, Density, and Size Distribution Effect of EPS Composition and Surface Characteristics on Granular Sludge Properties Effect of Wastewater on Physical Properties of Anaerobic Granular Sludge Discussion Anaerobic Granular Sludge Properties The Role of EPS and Sludge Surface Charge in Shaping Granular Sludge Properties Effect of Wastewater Type on Anaerobic Granular Sludge Properties Conclusion References 74 The role of Cohesive Forces in Anaerobic Granular Sludge Stability Introduction Materials and Methods Source of Granular Sludge Stability Test of Granular sludges Water and Chemicals Dissociation of Granular Sludge Dissociation index Granular Sludge Properties 80 _

5 Extracellular Polymeric Substances (EPS) Zeta Potential Granule Shape Properties Statistical Data Analysis Results Anaerobic Granular Sludge Stability Electrostatic Interactions Effect of the ph-value on Granular Sludge Stability The Effect of Ionic Strength on Granular Sludge Stability Ionic Interactions: The Effect of EDTA on Granular Sludge Stability Hydrogen Bonds: The Effect of Urea on the Granular Sludge Stability Role of the Wastewater Type in Shaping Cohesive Force Interactions Discussion Anaerobic Granular Sludge Stability " Electrostatic Interactions ^ Ionic Interactions: The Effect of EDTA on the granules' Stability Hydrogen Bonds: The Effect of Urea on the granules' Stability Wastewater Type and Cohesive Forces Relationship "" 4.5 Conclusion 9' 4.6 References " 5 Microbial Community Structure of Anaerobic Granular Sludge from Different Full-Scale Reactors 5.1 Introduction 5.2 Materials and Methods Source of Biomass Microbial Community Analysis ' Total DNA Extraction Polymerase Chain Reaction of 16SrRNA Gene Fragment for DGGE Analysis Denaturing Gradient Gel Electrophoresis (DGGE) Analysis Analysis of DGGE Patterns Cluster Analysis and Pairwise Permutation Tests of Significance Q l08 109

6 Estimation of Community Diversity from DGGE Profiles Results Microbial Community Structure Microbial Diversity Microbial Community- Granular Sludge Properties Relationship Discussion Conclusion References Enhancing Anaerobic Granular Sludge Formation Using Combined Addification- Ca 2+ addition (CAC) method Introduction Materials and Methods Inoculum Sludge Experimental Set-Up and Operation Specific Methanogenic Activity test (SMA) Analytical Methods Granular Size Distribution Results Reactor Performance Specific Methanogenic Activity (SMA) Granular Sludge Formation Effect of Combined Acidification-Ca 2+ -addition on Sludge Physicochemical characteristics Sludge Surface Properties Extracellular Polymeric Substances Ash Accumulation Discussion Cell Adsorption Cell Adhesion Conclusion References 145

7 7 Microbial Community Structure and Dynamics of Acidification/Ca 2 * Enhanced Anaerobic Granular Sludge Formation Introduction Materials and Methods Experimental Approach Microbial Community Analysis Total DNA Extraction Polymerase Chain Reaction of 16SrRNA Gene Fragment for DGGK analysis Denaturing Gradient Gel Electrophoresis Analysis of DGGE Patterns and Cluster Analysis Estimating Diversity of the Microbial Community from DGGE Profiles Results,«7.4.1 Microbial Population Structure Discussion,,-c Microbial Community Structure and Dynamics Anaerobic Granular Sludge Formation Model Conclusion., 7.7 References 8 Conclusions and recommendations List of Figures 10 List of Tables