Water Treatment Plant Performance Evaluations and Operations

Preface ix

1 Microscopic Particle Analysis 1

Bloomington Water Sources and Treatment Plant Processes 3

Number of Bacterial Cells in Natural and Treated Waters 11

Results of Microscopic Enumeration 11

Comparative Evaluation of Lime Softener/Clarifiers 14

Effect of Backwash on Filter Performance 14

Electronic Particle Counting for Evaluation of Filter Performance 18

Photomicrographs Using Epifluorescence Microscopy 19

Light Microscopy 20

References 20

2 Plant Process Evaluations 23

Particles Observed at Various Water Treatment Stages 23

Improving Filter Performance Following Backwash 26

References 32

3 Lime Softening 33

Plant Performance Evaluations 33

Removal of Organic Matter 40

Reference 40

4 Acidification Protocol 41

Regulation of Turbidity as a Microbiological Surrogate 41

Advanced Analytical Methods for Evaluation of Water Treatment Plant Performance 42

Formation of Particles During Treatment 44

Implications for Assessment of Water Treatment Plant Process Efficiency 46

Interim Enhanced Surface Water Treatment Rule 46

Acidification 47

Acidification Protocol 50

Alternate Exceedance Levels 51

References 51

5 Filter Operations 53

Particle Removal During Filtration 53

The Bloomington Filters 53

Filter Operations 57

Granular Activated Carbon Performance and Characteristics 60

Filter Media Size Distribution 64

Microbial Growth on Filter Media 68

Filter Effluent: Calcium Carbonate Post-Precipitation 70

Filter Washing 71

Procedure for Evaluating Biological Activity on Filter Media 73

Recommended Testing of Auxiliary Air Scour 73

References 74

6 Grit Removal 75

Gritting 76

ClariCone Settling Velocities Versus Applied Flow 81

Grit Removal Modification 83

Recarbonation Following Slurry Blanket Upset 85

Particle Size Analysis: Effect of Gritting 87

Post Grit 88

pH and Conductivity 89

Effect of Grit Removal on Blanket Stability 91

Revised Grit Removal Protocol 91

7 Lime Softener Performance Enhancements 95

Modified Lime Slurry Feed Points 95

Evaluation of Grit Removal Process 97

Reduction in Blanket Upsets Lime Overfeeds and Carbon Dioxide Requirements 100

Recarbonation Basins: Post-Precipitation Particle Size Analysis 100

Results of the Evaluation of the Gritting Process 102

Evaluation of the Inline Degritter 103

8 Lime Softener Operational Enhancements 107

Treatment Chemistry 108

Flow Rates to ClariCones 108

Energy Input to Impart Spiral Flow 109

Modification of Kinetic Energy Input 110

Effect of Gritting on Slurry Blanket 111

Effect of Blowdown on Sludge Blanket 112

Frequency of Intense Cleaning 112

Maintenance of Lime Delivery System 114

9 Granular Activated Carbon 117

Benefits of Granular Activated Carbon 117

Costs of Carbon 118

Reference 120

10 Plant Operations Manual 121

Development of Operations Manual and Guidelines Documents 121

Bloomington Water Supply History 121

Water Treatment Plant Processes 128

Laboratory Facilities 151

Shop Facilities 152

Operator’s Laboratory 154

Communications Between Operators and Operational Continuity 154

Future Development of Operational Guidelines 155

Reference 155

11 Taste-and-Odor Control 157

Nutrient Sources and Organism Growth 158

Laboratory Capabilities for Assessing Lake and Treated Water Quality 159

Destratification 162

Lake Source Water Protection 163

Odor Control: Operating Procedures and Processes 164

Finished Water Taste and Odor Monitoring 165

Operational Alternatives 165

Evaluation of Potential for Modified or Enhanced Treatment Process 165

Biodegradation: Bloomington’s Water Treatment Plant Operations Manual 169

Microscopic Examination and Description of Micrographs 170

Taste and Odor Remission and PAC Studies 171

Dominant Organisms in Evergreen Lake 172

Potential Future Trials 172

References 172

12 GAC Adsorption and Microbial Degradation 175

Removal of Geosmin on GAC 175

Removal of Geosmin Using Ozonated Air 181

Lake Water Monitoring for Geosmin and MIB 183

Follow-up Study of Temperature Effects 186

Ultraviolet Light plus Hydrogen Peroxide 187

Early Detection and Control of Impending Taste-and-Odor Episodes at Evergreen Lake 189

Implications for Plant Operational Control 190

Appendix A: Procedures for Total Bacterial Cell Count by Epifluorescence Microscopy 193

Appendix B: Potential Studies Involving Microscopic Particle Analysis: Particle Identification Enumeration and Sizing 199

Appendix C: Development of Operator Guidelines 203

Index 235