Sludge Reduction Technologies in Wastewater Treatment Plants

377 Pages·2013·8.721 MB·English

by  Foladori, Paola

Sludge Reduction
Technologies in Wastewater
Treatment Plants
A perfect system does not
stimulate new ideas
Sludge Reduction
Technologies in Wastewater
Treatment Plants
Paola Foladori, Gianni Andreottola and
Giuliano Ziglio
University of Trento
Italy
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Firstpublished2010
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ISBN10:184339378X
ISBN13:9781843392781
Contents
Preface ............................................................................................................ xiii
1 INTRODUCTION ....................................................................... 1
2 SLUDGE COMPOSITION AND PRODUCTION IN
FULL-PLANTS ........................................................................... 7
2.1 INTRODUCTION ........................................................................ 7
2.2 SLUDGE COMPOSITION ......................................................... 9
2.2.1 Sludge fractionation as COD ........................................... 10
2.3 SLUDGE PRODUCTION ........................................................... 12
2.3.1 Primary sludge production ............................................... 12
2.3.2 Biological excess sludge production ................................ 13
2.3.3 Calculation of biological excess sludge production ........ 13
2.4 TYPICAL SLUDGE PRODUCTION DATA ............................ 18
3 CURRENT SLUDGE DISPOSAL ALTERNATIVES AND
COSTS IN CRITICAL AREAS ................................................ 21
3.1 INTRODUCTION ........................................................................ 21
# 2010 IWA Publishing. Sludge Reduction Technologies in Wastewater Treatment Plants. By
PaolaFoladori,GianniAndreottolaandGiulianoZiglio.ISBN:9781843392781.PublishedbyIWA
Publishing,London,UK.
vi Sludge Reduction Technologies in Wastewater Treatment Plants
3.2 TOTAL COSTS FOR SLUDGE TREATMENT
AND DISPOSAL ......................................................................... 25
3.2.1 Sludge treatment costs in Europe .................................... 25
3.2.2 Sludge disposal costs in Europe ....................................... 26
4 PRINCIPLES OF SLUDGE REDUCTION TECHNIQUES
INTEGRATED IN WASTEWATER TREATMENT
PLANTS ....................................................................................... 29
4.1 INTRODUCTION ........................................................................ 29
4.2 CELL LYSIS AND CRYPTIC GROWTH ................................ 32
4.3 UNCOUPLED METABOLISM .................................................. 35
4.4 ENDOGENOUS METABOLISM ............................................... 37
4.5 MICROBIAL PREDATION ....................................................... 39
4.6 BIODEGRADABILITY INCREASE IN INERT SOLIDS ....... 40
4.7 HYDROTHERMAL OXIDATION ............................................. 41
5 OVERVIEW OF THE SLUDGE REDUCTION
TECHNIQUES INTEGRATED IN THE
WASTEWATER HANDLING UNITS ....................................... 43
5.1 ENZYMATIC HYDROLYSIS WITH ADDED
ENZYMES ................................................................................... 45
5.2 ENZYMATIC HYDROLYSIS BY THERMOPHILIC
BACTERIA (THERMOPHILIC AEROBIC REACTOR) ......... 46
5.3 MECHANICAL DISINTEGRATION ........................................ 47
5.4 ULTRASONIC DISINTEGRATION .......................................... 48
5.5 THERMAL TREATMENT ......................................................... 50
5.6 CHEMICAL AND THERMO-CHEMICAL
HYDROLYSIS ............................................................................. 50
5.7 OXIDATION WITH OZONE (OZONATION) ......................... 51
5.8 OXIDATION WITH STRONG OXIDANTS
(DIFFERENT FROM OZONE) .................................................. 53
5.9 ELECTRICAL TREATMENT .................................................... 55
5.10 ADDITION OF CHEMICAL METABOLIC
UNCOUPLERS ............................................................................ 57
5.11 SIDE-STREAM ANAEROBIC REACTOR
(AT AMBIENT TEMPERATURE) ............................................ 57
5.12 EXTENDED AERATION PROCESS ........................................ 59
5.13 MEMBRANE BIOLOGICAL REACTORS ............................... 60
5.14 GRANULAR SLUDGE ............................................................... 61
5.15 MICROBIAL PREDATION ....................................................... 62
Contents vii
6 OVERVIEW OF THE SLUDGE REDUCTION
TECHNIQUES INTEGRATED IN THE
SLUDGE HANDLING UNITS ................................................... 65
6.1 ENZYMATIC HYDROLYSIS WITH
ADDED ENZYMES .................................................................... 67
6.2 MECHANICAL DISINTEGRATION ........................................ 68
6.3 ULTRASONIC DISINTEGRATION .......................................... 69
6.4 THERMAL TREATMENT ......................................................... 70
6.5 MICROWAVE TREATMENT ................................................... 71
6.6 CHEMICAL AND THERMO-CHEMICAL
HYDROLYSIS ............................................................................. 73
6.7 OXIDATION WITH OZONE (OZONATION) ......................... 74
6.8 OXIDATION WITH STRONG OXIDANTS
(DIFFERENT FROM OZONE) .................................................. 74
6.9 ELECTRICAL TREATMENT .................................................... 76
6.10 AEROBIC DIGESTION .............................................................. 77
6.11 DIGESTION WITH ALTERNATING AEROBIC/ANOXIC/
ANAEROBIC CONDITIONS ................................................... 78
6.12 DUAL DIGESTION .................................................................. 79
6.13 AUTOTHERMAL THERMOPHILIC AEROBIC
DIGESTION ............................................................................... 81
6.14 ANAEROBIC DIGESTION ...................................................... 82
6.15 THERMOPHILIC ANAEROBIC DIGESTION ....................... 83
6.16 MICROBIAL PREDATION ..................................................... 83
6.17 WET AIR OXIDATION ........................................................... 84
6.18 SUPERCRITICAL WATER OXIDATION .............................. 86
7 PROCEDURES FOR ESTIMATING THE EFFICIENCY
OF SLUDGE REDUCTION TECHNOLOGIES ................. 89
7.1 INTRODUCTION ...................................................................... 89
7.2 COD AND TSS SOLUBILISATION ....................................... 91
7.3 DEGREE OF DISINTEGRATION ........................................... 92
7.3.1 Degree of disintegration based on COD
solubilisation (DD ) ................................................... 93
COD
7.3.2 Degree of disintegration based on oxygen
consumption .................................................................... 94
7.4 BIODEGRADABILITY EVALUATED
BY RESPIROMETRY ............................................................... 95
7.5 DENITRIFICATION RATE EVALUATED
BY NUR TEST .......................................................................... 97
viii Sludge Reduction Technologies in Wastewater Treatment Plants
7.6 ANAEROBIC BIODEGRADABILITY EVALUATED
BY BIOGAS PRODUCTION ................................................... 99
7.7 BACTERIA INACTIVATION .................................................. 100
7.8 EFFECT ON SLUDGE RETENTION TIME (SRT) ............... 102
7.9 MAXIMUM GROWTH YIELD, OBSERVED
BIOMASS YIELD, OBSERVED SLUDGE YIELD ............... 103
7.10 EVALUATION OF SLUDGE REDUCTION .......................... 105
7.11 TREATMENT FREQUENCY .................................................. 105
7.12 PHYSICAL PROPERTIES OF SLUDGE ................................ 106
8 BIOLOGICAL TREATMENTS ............................................. 109
8.1 INTRODUCTION ...................................................................... 109
8.2 RECENT INSIGHTS ON DEGRADABILITY OF SLUDGE
UNDER AEROBIC AND ANAEROBIC CONDITIONS ....... 112
8.2.1 Aerobic conditions .......................................................... 112
8.2.2 Anaerobic conditions ...................................................... 113
8.2.3 Disintegration of sludge flocs under anaerobic
conditions and in the presence of sulphides .................. 114
8.3 THE INFLUENCE OF AEROBIC/ANOXIC/ANAEROBIC
CONDITIONS ON HETEROTROPHIC MAXIMUM
GROWTH YIELD ..................................................................... 115
8.3.1 Process of denitrification þ nitrification ........................ 117
8.3.2 Digestion with alternating aerobic/anoxic/anaerobic
conditions ........................................................................ 118
8.4 SIDE-STREAM ANAEROBIC REACTOR
(AT AMBIENT TEMPERATURE) .......................................... 121
8.4.1 Oxic-Settling-Anaerobic process .................................... 121
8.4.2 Cannibal1 system ........................................................... 125
8.5 THERMOPHILIC ANAEROBIC DIGESTION ....................... 129
8.6 THERMOPHILIC AEROBIC REACTOR ............................... 131
8.6.1 Integration in the wastewater handling units
(S-TE process1) ............................................................. 134
8.6.2 Integration in the sludge handling units.
Dual digestion ................................................................. 137
8.6.3 Integration in the sludge handling units.
Autothermal thermophilic aerobic digestion ................. 138
8.7 ENZYMATIC HYDROLYSIS WITH
ADDED ENZYMES .................................................................. 140
8.8 ADDITION OF CHEMICAL METABOLIC
UNCOUPLERS .......................................................................... 144
Contents ix
8.9 PREDATION BY PROTOZOA AND METAZOA ................. 148
8.9.1 Types of predators .......................................................... 150
8.9.2 Process configuration and sludge reduction .................. 152
8.9.3 Pros and cons of microbial predation ............................ 159
8.10 EXTENDED AERATION PROCESSES ................................. 161
8.11 MEMBRANE BIOLOGICAL REACTORS (MBR) ................ 162
8.11.1 MBR þ physical, chemical treatments .......................... 163
8.12 GRANULAR SLUDGE ............................................................. 164
9 MECHANICAL DISINTEGRATION ................................... 167
9.1 INTRODUCTION ...................................................................... 167
9.2 TYPES OF EQUIPMENT FOR MECHANICAL
DISINTEGRATION .................................................................. 168
9.3 ENERGY LEVELS REQUIRED FOR SLUDGE
DISINTEGRATION .................................................................. 170
9.4 LYSIS-THICKENING CENTRIFUGE ..................................... 171
9.5 STIRRED BALL MILLS .......................................................... 174
9.6 HIGH PRESSURE HOMOGENISER ...................................... 178
9.7 HIGH PRESSURE JET AND COLLISION SYSTEM ............ 182
9.8 ROTOR-STATOR DISINTEGRATION SYSTEMS ............... 183
9.9 COMPARISON OF MECHANICAL
DISINTEGRATION TECHNIQUES ........................................ 185
10 ULTRASONIC DISINTEGRATION ..................................... 189
10.1 INTRODUCTION ...................................................................... 189
10.2 CONFIGURATIONS AND EQUIPMENT FOR
ULTRASONIC DISINTEGRATION ........................................ 191
10.3 EVALUATION OF ENERGY APPLIED IN
ULTRASONIC TREATMENT ................................................. 193
10.4 THE INFLUENCE OF ULTRASOUND FREQUENCY ........ 195
10.5 COD SOLUBILISATION ......................................................... 197
10.5.1 The influence of sludge concentration ........................... 199
10.6 INFLUENCE ON MICROORGANISMS ................................. 200
10.7 INFLUENCE ON SLUDGE SETTLEABILITY AND
DEWATERABILITY ................................................................ 203
10.8 INTEGRATION OF ULTRASONIC DISINTEGRATION
IN THE WASTEWATER HANDLING UNITS ...................... 203
10.9 INTEGRATION OF ULTRASONIC DISINTEGRATION
IN THE SLUDGE HANDLING UNITS .................................. 205