Handbook of Sludge Pumping, contents - Flygt

Contents
Chapter 1
Delimitation and purpose 4–7
1.1 List of abbreviations and acronyms 5
1.2 Classification of solids in sludge 6
Chapter 2
Fundamentals of liquid transportation in pipes 8–23
2.1 Pipe flow – turbulent, transitional, laminar 8
2.2 Fundamental rheological concepts 13
Chapter 3
This is sludge 24-33
3.1 Primary sludge 24
3.2 Secondary or activated sludge 25
3.3 Chemical sludge 26
3.4 External sludge 26
3.5 Thickened sludge 26
3.5.1 Gravity thickened sludge 27
3.5.2 Mechanically thickened sludge 28
3.6 Digested sludge 30
3.7 Dewatered sludge 30
3.8 Factors affecting the rheology of sludge 33
Chapter 4
Duty Point 34-57
4.1 Head loss calculations 34
4.1.1 System curve 35
4.1.2 The proposed way of assessing system loss 36
4.1.3 Losses in fittings 42
4.1.4 Assessment of system curves according to Frost 42
4.1.5 The rheological parameters 44
4.1.6 Head loss gradients to the first approximation 45
4.2 Change in pump performance due to sludge 48
4.2.1 Centrifugal pumps 48
4.2.2 Derating of Flygt Pumps in viscous
non-Newtonian liquids 48
4.2.3 Derating of centrifugal pumps according to
the Hydraulic Institute 50
4.2.4 The HI standard and non-Newtonian liquids 52
4.2.5 Required Net Positive Suction Head (NPSH) 53
4.2.6 Experimental motivation for the derating
rule of Flygt N-pumps 54
Chapter 5
Different Pump Technologies 58-79
5.1 Centrifugal Pumps 60
5.1.1 The Vortex Impeller Pump 61
5.1.2 Channel Impeller Pump 62
5.1.3 Semi-open Impeller Pumps 63
5.1.4 Self-priming centrifugal pump 66
5.2 Positive Displacement (PD) Pumps 69
5.2.1 Reciprocating Pumps 69
5.2.2 Air Operated Diaphragm Pumps (A.O.D. pumps) 70
5.2.3 Gear Pumps 71
5.2.4 Lobe Rotor Pumps 73
5.2.5 Sliding Vane Pumps 74
5.2.6 Progressive Cavity Pumps (PC-pumps) 75
5.2.7 PC-pump with a hopper design 78
5.2.8 Peristaltic Pumps 79
VI Contents

Chapter 6
Sludge pump applications, easy, difficult or hard? 80-109
6.1 The right pump for the right application 81
6.1.1 Different ways of installing an N-pump 82
6.2 Head loss, system design and pump characteristics 83
6.2.1 Factors influencing head loss 83
6.2.2 General system design recommendations 85
6.2.3 General recommendations if a centrifugal
pump is used for sludge pumping 87
6.2.4 General recommendations if a PC-pump is
used for sludge pumping 88
6.3 Removal of primary sludge 89
6.4 External/imported sludge transportation 91
6.5 Return activated sludge (RAS) pumping 93
6.6 Waste activated sludge (WAS) removal 95
6.7 Transportation of gravity thickened sludge 97
6.8 Transportation of mechanically thickened sludge 99
6.9 Digester recirculation 101
6.10 Digester withdrawal 103
6.11 Feeding sludge to a dewatering unit 104
6.12 Dewatered sludge transportation 106
6.13 Which pump for what application? 107
Chapter 7
Some real life applications 110-125
7.1 Overview 110
7.2 Digester recirculation in Rättvik WWTP, Sweden 110
7.2.1 Analysis of specific pump selection 112
7.2.2 Analysis of the piping system and associated pressure head loss 112
7.2.3 Analysis of the duty point 114
7.3 Feeding of a digester in Apeldoorn WWTP, the Netherlands 116
7.4 Emptying sludge hoppers with centrifugal pumps in
SNJ WWTP, Norway 119
7.5 Transportation of mechanically thickened sludge
in Bekkelaget WWTP, Norway 121
7.6 Digester recirculation at Naburn WWTP, Yorkshire, UK 123
Appendix A
Basic pumping theory 126-149
A1 Affinity laws 126
A2 Capacity 127
A3 Pump Head 128
A4 Power and efficiency 129
A5 Specific speed related to pump type 130
A6 Net Positive Suction Head or NPSH 132
A7 Inlet vortexes 134
A8 Performance curves for centrifugal pumps 134
A9 Viscosity 137
A10 System curves 138
A11 Serial and parallel pumping 143
A12 Speed control 144
A13 Positive Displacement Pumps 147
Appendix B
Questions to ask regarding sludge applications, PC-pump and N-pump 150-151
Bibliography 152-153
Index 154-159
Contents
VII