Tuning Biological Nutrient Removal Plants

Ken Hartley; Gustaf Olsson

BOOK

Tuning Biological Nutrient Removal Plants

Ken Hartley | Gustaf Olsson

(2013)

Additional Information

Book Details

ISBN: 978-1-78040-483-7
Edition: 1
Language: English
Pages: 264
Subjects: The environment
Environmental science, engineering & technology
Water supply & treatment

Abstract

Tuning Biological Nutrient Removal Plants increases interest in tuning to enhance both performance and capacity, to provide insight into typical plant operating characteristics, and to stimulate operators' interest in studying the behaviour of their own plants. The book focuses on understanding of plant behavioural characteristics so that optimum performance can be achieved and maintained.
Tuning Biological Nutrient Removal Plants is carefully organized to cover: influent and effluent characteristics; process fundamentals; individual process characteristics; overall plant characteristics; the evolutionary operation approach to tuning. The approach is practical and the use of mathematics is kept to a minimum and information is supplied in graphical and tabular form. Real operating data from a wide range of plant experiences is included.
The book draws on the generosity of many Australian plant owners in permitting their plant data to be incorporated. Not all process types are covered but the tuning principles expounded are universally applicable. The capacity and performance capabilities of a plant are not fixed; both are amenable to on-going enhancement through systematic and enthusiastic effort.
The book helps to set new benchmarks in plant operation. Tuning Biological Nutrient Removal Plants is a valuable resource for sewage treatment operations and operations support personnel, sewage process design engineers - operating authorities, consultants, contractors, operators of industrial wastewater treatment plants and sewage treatment lecturers in chemical engineering departments and other training organisations.
About the author: Ken Hartley, B.Tech, M.Eng.Sc Fellow, Institution of Engineers, Australia Member Australian Water Association Member International Water Association. Ken Hartley has 45 years' experience in the water and wastewater industry. He has worked for the South Australian water and wastewater authority, consultants GHD and the University of Queensland. Since 1998 he has been an independent consulting process engineer.

Section Title	Page	Action	Price
Cover\r	Cover
Contents	v
About the Authors	xi
Acknowledgements	xiii
Preface	xv
Chapter 1:\rWhat is tuning?	1
Chapter 2:\rInfluent and effluent characteristics	5
2.1 THE CATCHMENT	5
2.2 FLOW CHARACTERISTICS	6
2.3 MASS LOADING CHARACTERISTICS	9
2.3.1 Connected population	13
2.3.2 Flow	16
2.3.3 COD	16
2.3.4 SS	17
2.3.5 pH and alkalinity	17
2.3.6 Dissolved sulfide	17
2.3.7 TDS or conductivity	17
2.3.8 Pathogens	18
2.3.9 Load ratios	18
2.3.10 COD/BOD5	19
2.3.11 Nutrient ratios	19
2.3.12 Total COD fractions	19
2.3.13 Soluble unbiodegradable organic N	20
2.3.14 Nitrifier maximum specific growth rate	21
2.3.15 Temperature	21
2.3.16 Energy content	22
2.3.17 Other sewage components	22
2.4 SEWER TRANSFORMATIONS	23
2.5 EFFECT OF PRIMARY TREATMENT	23
2.6 EFFLUENT CHARACTERISTICS	23
Chapter 3:\rBiological nutrient removal - process fundamentals	27
3.1 THE BASIC PROCESS	27
3.2 KINETICS OF BIOLOGICAL PROCESSES	29
3.2.1 Substrate utilisation	29
3.2.2 Substrate concentration	30
3.3 SOLIDS RETENTION TIME\r	32
3.3.1 Definition	32
3.3.2 Calculation	32
3.4 CARBON REMOVAL	34
3.4.1 Effect of SRT	34
3.4.2 Loading conditions	35
3.4.3 F:M ratio	35
3.4.4 Mixed liquor suspended solids	36
Components of MLSS	36
Mass of solids	36
3.4.5 Nutrient requirements	38
3.4.6 Carbonaceous oxygen demand	39
3.5 NITROGEN REMOVAL\r	40
3.5.1 The nitrogen cycle	40
3.5.2 Nitrification	40
Nitrifiers	40
Kinetics	41
Ammonia-N (substrate) concentration3	42
Temperature	42
Salinity	44
Concurrent biological phosphorus removal	44
Alum dosing	44
Load variation	44
Unaerated mass fraction	45
Nitrification capacity	46
3.5.3 Denitrification	47
Stoichiometry	47
Kinetics	48
3.5.4 Simultaneous nitrification and denitrification	51
3.5.5 Total process oxygen demand	52
Steady state conditions	52
Dynamic conditions	53
3.6 PHOSPHORUS REMOVAL\r	53
3.6.1 Mechanisms	53
3.6.2 Process characteristics	55
3.6.3 Adverse factors	57
Dissolved oxygen and nitrate	58
Sulfide	58
PAO-GAO competition	59
3.7 SUPPLEMENTARY CHEMICAL DOSING	60
3.7.1 Phosphorus removal	60
3.7.2 Nitrogen removal	66
3.7.3 Other effects	66
3.8 ALKALINITY AND pH\r	67
3.8.1 Chemistry	67
3.8.2 Process behaviour	68
3.9 RULES OF THUMB	69
Chapter 4:\rSludge settleability	71
4.1 CHARACTERISING SETTLEABILITY	71
4.2 SETTLING RATES	73
4.3 FACTORS AFFECTING SETTLEABILITY	75
4.3.1 Non-BNR activated sludge processes	75
Feed quality	75
Operating parameters	75
Reactor mixing characteristics	76
4.3.2 BNR processes	76
Anoxic fraction	76
Influent RBCOD	79
Chemical dosing	80
4.4 EFFECT OF SVI ON EFFLUENT QUALITY	80
4.5 FOAMING	81
Chapter 5:\rBNR flowsheets	83
5.1 NITROGEN REMOVAL\r	83
5.1.1 Modified Ludzack-Ettinger (MLE)	83
5.1.2 Bardenpho	83
5.2 PHOSPHORUS REMOVAL\r	84
5.2.1 Phoredox	84
5.3 NITROGEN AND PHOSPHORUS REMOVAL\r	84
5.3.1 Modified Bardenpho	84
5.3.2 Johannesburg (JHB)	84
5.3.3 University of Cape Town (UCT)	84
5.3.4 Modified UCT (MUCT)	84
5.3.5 Westbank	85
5.3.6 Membrane Bioreactor (MBR)	85
Chapter 6:\rReactors	89
6.1 MIXING	89
6.1.1 Mixing regime	89
Complete mix	89
Plug flow	91
Arbitrary flow	91
Time constant	94
6.1.2 Mixing intensity	94
Active mixing	94
Flocculation	94
6.2 AERATION	96
6.2.1 Oxygen transfer rate	96
6.2.2 Oxygen transfer efficiency	99
6.2.3 Carbon dioxide stripping	99
6.3 COMPARTMENTALISED REACTORS\r	100
6.3.1 Description	100
6.3.2 Process characteristics	100
6.3.3 Operating principles	103
6.4 OXIDATION DITCHES\r	103
6.4.1 Description	103
6.4.2 Process characteristics	103
6.4.3 Hydraulics	107
6.4.4 Mechanical aerator characteristics	109
Horizontal shaft aerators	109
Vertical shaft aerators	109
6.4.5 Operating principles	110
6.5 MEMBRANE BIOREACTORS\r	110
6.5.1 Description	110
6.5.2 Process characteristics	111
Bioreactor	111
Membranes	113
6.5.3 Operating principles	115
6.6 SEQUENCING BATCH REACTORS\r	115
6.6.1 Description	115
6.6.2 Process characteristics	116
6.6.3 Operating principles	120
Chapter 7:\rSecondary clarifiers	121
7.1 DESCRIPTION	121
7.2 MASS BALANCES	122
7.3 OPERATING DIAGRAMS	124
7.4 EFFLUENT QUALITY\r	127
7.4.1 Factors affecting effluent SS	127
Degree of flocculation	128
Environmental chemistry	128
SRT	128
SSVI	129
MLSS concentration	129
Chemical precipitant dosing	130
Overflow and settling rates	132
Rising sludge	133
7.4.2 Other effects of clarifiers on effluent quality	133
7.5 CLARIFIER STRESS TESTING	133
Chapter 8:\rSludge processes	137
8.1 OVERVIEW	137
8.2 AEROBIC DIGESTION	137
8.2.1 Stabilisation performance	138
8.2.2 Operating characteristics	140
8.2.3 Operating examples	141
West Byron STP	141
Brunswick Valley STP	143
8.2.4 Operating principles	145
8.3 SLUDGE DEWATERING	145
8.3.1 Mass balances	145
8.3.2 Belt filter press	146
8.3.3 Centrifuge	148
Chapter 9:\rPlant characteristics	155
9.1 MASS BALANCES	155
RAS concentration	155
Sludge thickeners	156
Sludge dewatering	157
Dewatered sludge P content	157
Biological P removal	157
9.2 OPERATIONAL PROCESS CAPACITY	157
9.2.1 Bottlenecks	158
9.2.2 Failure curves	159
9.3 CAPACITY ENVELOPES	159
9.3.1 Continuous flow process	160
9.3.2 SBR process	162
9.4 ENERGY CONSUMPTION	164
9.4.1 Water cycle	164
9.4.2 Plant energy balance	165
9.4.3 Energy models	166
General	166
Plant-specific energy characteristics	168
MBRs	168
9.4.4 Tuning	170
Chapter 10:\rProcess control	171
10.1 THE ROLE OF CONTROL AND AUTOMATION	171
10.2 DISTURBANCES	172
10.3 CONTROL PRIORITIES\r	173
10.3.1 The system	173
10.3.2 The importance of dynamics	173
10.3.3 Modelling	174
10.4 FEEDBACK CONTROL	174
10.4.1 Open and closed loop control	174
10.4.2 Low level control	176
10.4.3 Integral action	178
10.4.4 Derivative action	178
10.4.5 Computer realisation of the PID controller	179
10.4.6 When is PID control appropriate?	179
10.4.7 Controller tuning	180
10.4.8 Manual PI tuning	181
10.4.9 Ziegler-Nichols frequency response method	182
10.4.10 Autotuning	183
10.5 INSTRUMENTATION AND MONITORING\r	183
10.5.1 Instruments	183
10.5.2 Estimating the oxygen uptake rate	184
10.6 PUMPING\r	185
10.6.1 Pump characteristics	185
10.6.2 Relationship between flow rate and power	187
10.7 ESSENTIAL CONTROL LOOPS	188
10.7.1 Dissolved oxygen control	188
10.7.2 Ammonia-Based DO control	192
10.7.3 Recycle flow controls	193
10.7.4 Chemical precipitation	193
10.7.5 Anaerobic digestion process control	194
10.8 MINIMISING OPERATING COST\r	195
10.8.1 Approaches	195
10.8.2 The human factor	195
10.9 CONCLUDING REMARKS	196
Chapter 11:\rEvolutionary operation	197
11.1 LEARNING	197
11.2 APPLICATION TO SEWAGE TREATMENT PLANTS\r	198
11.2.1 Plant improvement strategies	198
11.2.2 Learning curves	199
11.2.3 Startup phase	200
Experience	200
Contractual startups	203
11.3 LONG-TERM IMPROVEMENT\r	204
11.3.1 Potential	204
11.3.2 Tuning	205
11.3.3 Stress testing	206
11.3.4 Debottlenecking	207
11.3.5 Costs	207
11.4 EVOP PROCEDURES	209
11.4.1 Method	209
Step 1: Data collection	210
Step 2: Data interpretation	213
Step 3: Process adjustment	213
11.4.2 Trend plots	214
11.4.3 General principles	220
11.5 FAUX EVOP	221
Appendix 1:\rA note on the statistics of variability	223
AVERAGE AND MEDIAN	223
PERCENTILES	223
APPLICATION	224
Appendix 2:\rChemicals: useful properties	227
Appendix 3:\rAbbreviations	231
References	233
Index	241

Tuning Biological Nutrient Removal Plants

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