Solids Separation Problems p. 1 Introduction p. 1 Solids Separation Problems p. 1 Activated Sludge Floc p. 1 Solids Separation Problems in Terms of

Transcription

1 Solids Separation Problems p. 1 Introduction p. 1 Solids Separation Problems p. 1 Activated Sludge Floc p. 1 Solids Separation Problems in Terms of Floc Structure p. 3 Dispersed Growth p. 3 Viscous Bulking p. 3 Pin Floc p. 4 Filamentous Bulking p. 4 Foam/Scum p. 5 Differentiation of Microbial and Process-Related Solids Separation Problems p. 7 Methods p. 9 Introduction p. 9 Microscopic Examination Methods p. 9 Filament Counting Methods p. 9 Total Extended Filament Length p. 9 Filament Count p. 9 Nocardioform Filament Organism Counting p. 9 Floc and Filamentous Microorganism Characterization p. 9 Introduction p. 9 Sampling Points p. 10 Sampling Frequency p. 11 Sample Transport and Storage p. 11 Microscope p. 12 Cameras p. 13 Staining Procedures p. 13 Sample Preparation p. 13 Floc Characteristics and Overall Filament Abundance p. 14 Floc Size p. 15 Floc Characteristics p. 15 Protozoa and Other Macroorganisms p. 15 Nonbiological Organic and Inorganic Particles p. 15 Bacterial Colonies p. 15 Cells Dispersed in Bulk Solution p. 16 Effects of Filamentous Organisms on Floc Structure p. 17 Filamentous Organism Abundance p. 17 Filamentous Organism Characteristics p. 17 Branching p. 17 Motility p. 18 Filament Shape p. 18 Location p. 18

2 Attached Bacteria p. 18 Sheath p. 18 Cross-Walls (Cell Septa) p. 19 Filament Width p. 19 Filament Length p. 19 Cell Shape p. 19 Cell Size p. 19 Sulfur Deposits p. 21 Other Granules p. 21 Staining Reactions p. 21 Additional Observations p. 22 Filamentous Organism Identification p. 23 Using the Dichotomous Key p. 23 Building Your Skills p. 23 Filamentous Organism Descriptions p. 23 Sphaerotilus natans (Figures 2.9c, 2.13b, 2.14f, and 2.21a) p. 24 Type 1701 (Figure 2.21b) p. 24 Haliscomenobacter hydrossis (Figure 2.21c) p. 27 Type 021N (Figures 2.11b, 2.13d, 2.14d, 2.14e, 2.15c, 2.18a, 2.19b, and 2.22a) p. 27 Thiothrix I (Figures 2.14b, 2.15a, 2.19c, and 2.23a) p. 27 Thiothrix II (Figures 2.19d, 2.23c, and 2.23d) p. 28 Type 0914 (Figures 2.15d, 2.24a, and 2.24b) p. 29 Beggiatoa sp. (Figures 2.15b, 2.22c, and 2.22d) p. 30 Nostocoida limicola I (Figure 2.25a) p. 30 Nostocoida limicola II (Figures 2.10e, 2.11c, 2.17b, 2.18e, and 2.25b) p. 32 Nostocoida limicola III (Figure 2.25c) p. 33 Type 0411 (Figure 2.26a) p. 34 Type 0961 (Figure 2.26b) p. 34 Type 0092 (Figures 2.18d and 2.26c) p. 35 Type 0581 (Figure 2.26d) p. 35 Type 0041 (Figures 2.10a, 2.12a, 2.13c, 2.14a, 2.17c, 2.18f, and 2.27a) p. 35 Type 0675 (Figure 2.27b) p. 37 Type 1851 (Figures 2.17d and 2.27c) p. 37 Type 0803 (Figure 2.27d) p. 37 Microthrix parvicella (Figures 2.17e, 2.18c, 2.28a, 5.1e, and 5.1f) p. 37 Nocardioforms (Figures 2.9b, 2.10f, 2.14g, 2.17f, 2.18b, 2.28b, 5.1a, 5.1b, 5.1c and 5.1d) p. 37 Type 1863 (Figures 2.10c, 2.14c, and 2.28c) p. 37 Type 0211 (Figure 2.28d) p. 41 Flexibacter sp. (Figure 2.29a) p. 43 Bacillus sp. (Figure 2.29b) p. 43 Cyanophyceae (Figure 2.29c) p. 43

3 Fungi (Figures 2.9a and 2.29d) p. 43 Progress in Identifying Filamentous Organisms p. 44 Protozoa And Metazoa p. 45 General p. 45 Microscopic Evaluation p. 46 Taxonomic Classification p. 47 Flagellates p. 47 Amoebae p. 47 Free-Swimming Ciliates p. 47 Attached Ciliates p. 48 Rotifers p. 48 Higher Invertebrates p. 48 Use of Protozoa and Metazoa as Indicator Organisms p. 48 Physical and Chemical Methods p. 49 Settling Tests p. 50 Foaming Tests p. 50 Methods for Differentiating Microbiological and Process-Related Solids Separation Problems p. 51 Dispersed SS (DSS) p. 51 Flocculated SS (FSS) p. 51 Secondary Effluent SS (ESS) p. 52 Applications and Results of Microscopic Examination of Activated Sludge p. 57 Introduction p. 57 Filament Counting p. 57 Filamentous Organism Identification in Activated Sludge p. 58 Results of Filamentous Organism Surveys p. 58 Diagnosis of Causes of Solids Separation Problems through Microscopic Examination p. 59 General p. 59 Nonmicrobial Particles p. 60 Other Microbiological Features p. 61 General p. 61 Limited Diversity p. 61 Dispersed Growth p. 62 Neisser-Positive Cell Clumps p. 65 Yeast p. 66 Zoogloeas p. 66 Selector Flocs p. 66 Nitrifying Bacteria p. 67 Denitrifying Bacteria p. 67 Spirochaetes, Spirillum, and Flexibacter p. 67 Exocellular Material p. 67

4 Algae p. 68 Filamentous Organisms p. 69 Relationship to Causes of Bulking p. 69 Nutrient Balance p. 69 Readily Metabolizable Soluble Organics p. 69 Sulfide p. 70 Lipids p. 70 Other Particulate Substrates p. 70 Case Study p. 70 Net Growth Rate (MCRT, F/M) p. 71 Aeration Basin Configuration and Redox Conditions p. 71 Wastewater Feeding Regime p. 72 Foam Trapping Features p. 72 Upstream Biological Treatment Units, Sewer Surfaces, and In-Plant Surfaces p. 73 DO Concentration p. 73 ph p. 73 Temperature p. 73 Summary p. 74 Control of Activated Sludge Bulking and Other Settling Problems p. 77 Introduction p. 77 General Approach p. 77 Rapid, Nonspecific Bulking Control Methods p. 78 Manipulation of RAS Flow Rates and Aeration Basin Feed Points p. 78 Secondary Clarifier Operating Principles p. 78 Activated Sludge Process Schematic and Definitions p. 78 Secondary Clarifier Process Operating Relationships p. 78 Degree of Thickening Achieved by Secondary Clarifier p. 79 Required RAS Flow Rate p. 79 Secondary Clarifier Capacity p. 79 Sludge Thickening Theory p. 79 Secondary Clarifier Analysis and Operation p. 83 System Analysis and Operation p. 85 Addition of Chemicals and Inert Solids to Enhance Activated Sludge Settling Rates p. 87 Addition of Disinfectants to Selectively Kill Filamentous Organisms p. 89 General p. 89 Use of Chlorination for Bulking Control p. 90 Chlorination Criteria p. 90 General Guidelines p. 92 Chlorination System Design p. 93 Monitoring Effects of Chlorine Addition p. 93 Case Histories of Bulking Control Using Chlorination p. 94

5 General p. 94 City of Albany, GA p. 94 City of San Jose/Santa Clara Water Pollution Control Plant, CA p. 96 Stroh Brewing Co., Longview, TX p. 97 Plastics Manufacturing Wastewater Activated Sludge System, WV p. 98 Use of Hydrogen Peroxide for Bulking Control p. 101 General p. 101 City of Petaluma, CA p. 102 Use of Ozone for Bulking Control p. 102 Filamenticides p. 102 Specific Methods of Bulking Control p. 102 Nutrient Deficiency p. 103 General p. 103 Macronutrient Deficiency p. 103 General p. 103 Factors Affecting Macronutrient Requirements p. 103 Availability of Macronutrients p. 103 Satisfying Macronutrient Demands p. 104 Required Residual Macronutrient Concentrations p. 106 Micronutrients p. 107 Low Dissolved Oxygen (DO) Concentrations p. 108 General p. 108 Case Histories p. 109 Orange County Sanitation District Plant, Fountain Valley, CA p. 109 Pulp and Paper Wastewater Activated Sludge Plant p. 109 City of Woonsocket, RI p. 109 Effect of Aeration Basin Configuration, Wastewater Feeding Method, and Redox Conditions on Activated Sludge Settling Characteristics p. 110 Effect of Aeration Basin Configuration p. 110 Selectors p. 111 Selector Effect p. 112 General Observations p. 112 Selector Mechanisms p. 112 Effects of Selectors p. 117 Selector Design (Sizing) p. 118 General p. 118 Initial Contact Zones p. 118 Aerobic Selectors p. 118 Anoxic Selectors p. 119 Anaerobic Selectors p. 120 Main Aeration Basin p. 120 Selector Case Histories p. 120

6 Leopoldsdorf Sugar Mill, Austria p. 120 Hamilton, OH p. 120 Davenport, IA p. 122 Tri-City, Clackamas County, OR p. 123 Fayetteville, AR p. 124 Hyperion Treatment Plant, Los Angeles, CA p rd Avenue Plant, Phoenix, AZ p. 125 Situations Where Selectors Are Not Effective p. 126 High Effluent SS Due to Clarification Problems p. 127 General p. 127 Problem Definition p. 128 Method of Investigation p. 128 Results p. 128 Problem Resolution p. 128 Inadequate Flocculation, Floc Break-Up (High ESS, High DSS[subscript i], Low FSS) p. 128 Clarifier Hydraulic Problems (High ESS, Low DSS, Low FSS) p. 129 Bioflocculation Problems (High DSS[subscript i], High FSS, High ESS) p. 129 Activated Sludge Foaming and Control p. 131 Activated Sludge Foaming p. 131 Types of Activated Sludge Foam p. 131 Nocardioform Foaming p. 132 Extent and Significance of Problems p. 132 Foaming Organism Surveys p. 132 Foaming Problems p. 132 Activated Sludge p. 132 Anaerobic Digesters p. 133 Pathogenic Nocardioforms p. 135 Proposed Mechanisms of Foaming p. 135 Introduction p. 135 Physical/Chemical Factors p. 135 Nature of Foam p. 135 Solids-Containing Foams p. 136 Roles of Surfactants p. 136 Anaerobic Digester Foaming p. 137 Foam Trapping and Recycling p. 137 Foaming Tests p. 139 Microbiological Factors p. 140 Factors Affecting Growth p. 140 MCRT and Temperature p. 141 ph p. 143 Nocardioform Control p. 144

7 Nocardioform Growth in Activated Sludge p. 144 Introduction p. 144 Aerobic Selectors p. 144 Anoxic Selectors p. 146 Anaerobic Selectors p. 147 Classifying Selectors and Selective Foam Wasting p. 151 Chlorination p. 154 Cationic Polymer Addition p. 154 Automatic MCRT Control p. 156 Microthrix parvicella p. 156 Factors Affecting M. parvicella Growth p. 156 General p. 156 Substrates p. 156 Operating Conditions p. 156 Control p. 158 Case Histories p. 158 Upper Occoquan Sewage Authority (UOSA), VA p. 158 Northside Wastewater Treatment Plant, Tulsa, OK p. 159 Anaerobic Digester Foaming p. 160 Bibliography and References p. 163 Index p. 179 Table of Contents provided by Blackwell's Book Services and R.R. Bowker. Used with permission.